docs/index.html

   1 <!DOCTYPE html>
   2 <html>
   3   <head>
   4     <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
   5     <title>dygraphs JavaScript Visualization Library</title>
   6     <!--[if IE]>
   7       <script type="text/javascript" src="excanvas.js"></script>
   8     <![endif]-->
   9     <script type="text/javascript" src="dygraph-combined.js"></script>
  10     <link rel="stylesheet" href="style.css">
  11
  12     <!-- Google Analytics -->
  13     <script type="text/javascript">
  14       var _gaq = _gaq || [];
  15       _gaq.push(['_setAccount', 'UA-769809-2']);
  16       _gaq.push(['_trackPageview']);
  17       (function() {
  18         var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
  19         ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
  20         var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
  21       })();
  22     </script>
  23   </head>
  24   <body>
  25     <div id="nav">
  26       <h2>Documentation</h2>
  27       <ul>
  28         <li><a href="#demo">Demo</a></li>
  29         <li><a href="#usage">Usage</a></li>
  30         <li><a href="#ie">IE Compatibility</a></li>
  31         <li><a href="#gviz">GViz Data</a></li>
  32         <li><a href="#baseball">Baseball chart</a></li>
  33         <li><a href="#stock">Stock chart</a></li>
  34         <li><a href="#options">Options Reference</a></li>
  35         <li><a href="#gwt">GWT Compatibility</a></li>
  36         <li><a href="#policy">Data Policy</a></li>
  37       </ul>
  38
  39       <h2>Features</h2>
  40       <ul>
  41         <li><a href="data.html">Data Formats</a></li>
  42         <li><a href="annotations.html">Annotations</a></li>
  43       </ul>
  44
  45       <h2>Project</h2>
  46       <ul>
  47         <li><a href="http://github.com/danvk/dygraphs">Source</a></li>
  48         <li><a href="http://code.google.com/p/dygraphs/issues/">Issues</a></li>
  49         <li><a href="http://code.google.com/p/dygraphs/issues/entry">Report Bug</a></li>
  50         <li><a href="changes.html">Contribute a change</a></li>
  51         <li><a href="mailto:dygraphs-users [at] googlegroups.com">Contact</a></li>
  52       </ul>
  53
  54       <h2>Gallery</h2>
  55       <ul>
  56         <li><a href="tests/">(browse demos)</a></li>
  57         <li><a href="tests/demo.html">Basic Demo</a></li>
  58         <li><a href="tests/gviz.html">GViz Demo</a></li>
  59         <li><a href="tests/plotter.html">Equation Plotter</a></li>
  60         <li><a href="tests/perf.html">Performance Test</a></li>
  61         <li><a href="tests/annotation.html">Annotations</a></li>
  62         <li><a href="tests/annotation-gviz.html">Annotations (GViz)</a></li>
  63         <li><a href="tests/fillGraph.html">Filled Chart</a></li>
  64         <li><a href="tests/perf.html">Fractions</a></li>
  65         <li><a href="tests/visibility.html">Visibility</a></li>
  66         <li><a href="tests/label-div.html">Labels in a DIV</a></li>
  67         <li><a href="tests/numeric-axis.html">Numeric Axis</a></li>
  68         <li><a href="tests/draw-points.html">Dotted Points</a></li>
  69         <li><a href="tests/native-format.html">Native Format</a></li>
  70         <li><a href="tests/grid_dot.html">Crazy Styles</a></li>
  71         <li><a href="tests/spacing.html">Tick spacing</a></li>
  72         <li><a href="tests/callback.html">Callbacks</a></li>
  73         <li><a href="tests/crosshair.html">Crosshairs</a></li>
  74         <li><a href="tests/hourly.html">Hourly/Minutely data</a></li>
  75         <li><a href="tests/isolated-points.html">Isolated Points</a></li>
  76         <li><a href="tests/missing-data.html">Missing Data</a></li>
  77         <li><a href="tests/border.html">Bordered chart</a></li>
  78         <li><a href="tests/custom-bars.html">Custom Bars</a></li>
  79         <li><a href="tests/customLabel.html">Custom Label Styles</a></li>
  80         <li><a href="tests/dygraph.html">Minimal Example</a></li>
  81         <li><a href="tests/negative.html">Negative Numbers</a></li>
  82         <li><a href="tests/noise.html">Noisy Data</a></li>
  83         <li><a href="tests/two-series.html">Multiple Series</a></li>
  84         <li><a href="tests/highlighted-region.html">Custom Underlay / background</a></li>
  85         <li><a href="tests/zoom.html">Tests for zoom operations</a></li>
  86         <li><a href="tests/logscale.html">Log scale tests</a></li>
  87       </ul>
  88     </div>
  89
  90     <div id="content">
  91       <h1>dygraphs JavaScript Visualization Library</h1>
  92
  93       <p><a href="http://github.com/danvk/dygraphs">http://github.com/danvk/dygraphs</a></p>
  94       <p>See <a href="http://groups.google.com/group/dygraphs-users">mailing list</a>, <a href="http://github.com/danvk/dygraphs/downloads/">downloads</a>, <a href="tests/">gallery</a> and <a href="http://code.google.com/p/dygraphs/issues/">open issues</a></p>
  95
  96       <p>dygraphs is an open source JavaScript library that produces produces interactive, zoomable charts of time series. It is designed to display dense data sets and enable users to explore and interpret them.</p>
  97
  98       <h3 id="demo">A demo is worth a thousand words:</h3>
  99
 100       <p style="font-size:0.8em">(Mouse over to highlight individual values. Click and drag to zoom. Double-click to zoom back out. Change the number and hit enter to adjust the averaging period.)</p>
 101
 102       <div id="title" style="width:800px; margin: 1em;text-align:center; font-weight: bold; font-size: 125%;">Temperatures in New York vs. San Francisco</div>
 103
 104       <div id="demodiv" style="width:800px; height:320px;"></div>
 105       <script type="text/javascript">
 106         g = new Dygraph(
 107           document.getElementById("demodiv"),
 108           "ny-vs-sf.txt",
 109           {
 110             rollPeriod: 14,
 111             showRoller: true,
 112             customBars: true,
 113             yAxisLabelWidth: 30,
 114             title: 'Temperatures in New York vs. San Francisco',
 115             ylabel: 'Temperature (F)'
 116           }
 117         );
 118       </script>
 119
 120       <h4>Some things to notice:</h4>
 121       <ul>
 122         <li>There's less seasonal temperature variation in SF than in NY.</li>
 123         <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.</li>
 124         <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.</li>
 125         <li>Using a 14-day moving average makes it clearer. A 100-day rolling period averages out nearly all the specifics from the data.</li>
 126         <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).</li>
 127         <li>The bands around each point indicate average highs and lows.</li>
 128         <li>There is a <em>lot</em> of data in this chart: low, average and high for each city on each day of a three year period &asymp; 6000 data points in all.</li>
 129       </ul>
 130
 131       <p>dygraphs allows the user to explore the data and discover these facts.</p>
 132
 133       <p>For more demos, browse the dygraph <a href="tests/">tests</a> directory.</p>
 134
 135       <h3>Features</h3>
 136       <p>Some of the features of dygraphs:</p>
 137       <ul>
 138         <li>Plots time series without using an external server or Flash</li>
 139         <li>Works in Internet Explorer (using excanvas)</li>
 140         <li>Lightweight (69kb) and responsive</li>
 141         <li>Displays values on mouseover (this makes it easily discoverable)</li>
 142         <li>Supports error bands around data series</li>
 143         <li>Interactive zoom</li>
 144         <li>Displays Annotations on the chart</li>
 145         <li>Adjustable averaging period</li>
 146         <li>Can intelligently chart fractions</li>
 147         <li>Customizable click-through actions</li>
 148         <li>Compatible with the Google Visualization API</li>
 149         <li>Intelligent defaults make it easy to use</li>
 150       </ul>
 151
 152       <h2 id="usage">Usage</h2>
 153
 154       <p>To use dygraphs, include the <code><a href="http://github.com/danvk/dygraphs/downloads/">dygraph-combined.js</a></code> JavaScript file and instantiate a <code>Dygraph</code> object.</p>
 155
 156       <p>Here's a basic example to get things started:</p>
 157
 158       <div class="example" style="clear:both;">
 159         <div class="codeblock" style="float:left;width:400px;">
 160           <h3 style="text-align:center">HTML</h3>
 161           <code>
 162   <pre>
 163 &lt;html&gt;
 164 &lt;head&gt;
 165 &lt;script type=&quot;text/javascript&quot;
 166   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 167 &lt;/head&gt;
 168 &lt;body&gt;
 169 &lt;div id=&quot;graphdiv&quot;&gt;&lt;/div&gt;
 170 &lt;script type=&quot;text/javascript&quot;&gt;
 171   g = new Dygraph(
 172
 173     // containing div
 174     document.getElementById(&quot;graphdiv&quot;),
 175
 176     // CSV or path to a CSV file.
 177     &quot;Date,Temperature\n&quot; +
 178     &quot;2008-05-07,75\n&quot; +
 179     &quot;2008-05-08,70\n&quot; +
 180     &quot;2008-05-09,80\n&quot;
 181
 182   );
 183 &lt;/script&gt;
 184 &lt;/body&gt;
 185 &lt;/html&gt;
 186 </pre>
 187           </code>
 188         </div>
 189         <div class="codeoutput" style="float:left;">
 190           <h3 style="text-align:center">OUTPUT</h3>
 191           <div id="graphdiv"></div>
 192           <script type="text/javascript">
 193             g = new Dygraph(
 194
 195               // containing div
 196               document.getElementById("graphdiv"),
 197
 198               // CSV or path to a CSV file.
 199               "Date,Temperature\n" +
 200               "2008-05-07,75\n" +
 201               "2008-05-08,70\n" +
 202               "2008-05-09,80\n"
 203             );
 204           </script>
 205         </div>
 206       </div>
 207
 208       <p style="clear:both">In order to keep this example self-contained, the second parameter is raw CSV data. The dygraphs library parses this data (including column headers), resizes its container to a reasonable default, calculates appropriate axis ranges and tick marks and draws the graph.</p>
 209
 210       <p>In most applications, it makes more sense to include a CSV file instead. If the second parameter to the constructor doesn't contain a newline, it will be interpreted as the path to a CSV file. The Dygraph will perform an XMLHttpRequest to retrieve this file and display the data when it becomes available. Make sure your CSV file is readable and serving from a place that understands XMLHttpRequest's! In particular, you cannot specify a CSV file using <code>"file:///"</code>. Here's an example: (data from <a href="http://www.wunderground.com/history/airport/KNUQ/2007/1/1/CustomHistory.html?dayend=31&amp;monthend=12&amp;yearend=2007&amp;req_city=NA&amp;req_state=NA&amp;req_statename=NA">Weather Underground</a>)</p>
 211
 212       <div class="example" style="clear:both;">
 213         <div class="codeblock" style="float:left;width:400px;">
 214           <h3 style="text-align:center">HTML</h3>
 215           <code>
 216 <pre>
 217 &lt;html&gt;
 218 &lt;head&gt;
 219 &lt;script type=&quot;text/javascript&quot;
 220   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 221 &lt;/head&gt;
 222 &lt;body&gt;
 223 &lt;div id=&quot;graphdiv2&quot;
 224   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 225 &lt;script type=&quot;text/javascript&quot;&gt;
 226   g2 = new Dygraph(
 227     document.getElementById(&quot;graphdiv2&quot;),
 228     &quot;temperatures.csv&quot;, // path to CSV file
 229     {}          // options
 230   );
 231 &lt;/script&gt;
 232 &lt;/body&gt;
 233 &lt;/html&gt;
 234 </pre>
 235           </code>
 236         </div>
 237         <div class="codeoutput" style="float:left;">
 238           <h3 style="text-align:center">OUTPUT</h3>
 239           <div id="graphdiv2" style="width:500px; height:300px;"></div>
 240           <script type="text/javascript">
 241             g2 = new Dygraph(
 242               document.getElementById("graphdiv2"),
 243               "temperatures.csv",
 244               {}
 245             );
 246           </script>
 247         </div>
 248       </div>
 249
 250       <p style="clear:both;">The file used is <code><a href="temperatures.csv">temperatures.csv</a></code>.</p>
 251
 252       <p>There are a few things to note here:</p>
 253
 254       <ul>
 255         <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
 256         <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
 257         <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
 258         <li>The labels on the x-axis have switched from days to months. If you zoom in, they'll switch to weeks and then days.</li>
 259         <li>Some heuristics are used to determine a good vertical range for the data. The idea is to make all the data visible and have human-friendly values on the axis (i.e. 200 instead of 193.4). Generally this works well.</li>
 260         <li>The data is very spiky. A moving average would be easier to interpret.</li>
 261       </ul>
 262
 263       <p>This problem can be fixed by specifying the appropriate options in the "additional options" parameter to the Dygraph constructor. To set the number of days for a moving average, use the <code>rollPeriod</code> option. Here's how it's done:</p>
 264
 265       <div class="example" style="clear:both;">
 266         <div class="codeblock" style="float:left;width:400px;">
 267           <h3 style="text-align:center">HTML</h3>
 268           <code>
 269 <pre>
 270 &lt;html&gt;
 271 &lt;head&gt;
 272 &lt;script type=&quot;text/javascript&quot;
 273   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 274 &lt;/head&gt;
 275 &lt;body&gt;
 276 &lt;div id=&quot;graphdiv3&quot;
 277   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 278 &lt;script type=&quot;text/javascript&quot;&gt;
 279   g3 = new Dygraph(
 280     document.getElementById(&quot;graphdiv3&quot;),
 281     &quot;temperatures.csv&quot;,
 282     {
 283       rollPeriod: 7,
 284       showRoller: true
 285     }
 286   );
 287 &lt;/script&gt;
 288 &lt;/body&gt;
 289 &lt;/html&gt;
 290 </pre>
 291           </code>
 292         </div>
 293         <div class="codeoutput" style="float:left;">
 294           <h3 style="text-align:center">OUTPUT</h3>
 295           <div id="graphdiv3" style="width:500px; height:300px;"></div>
 296           <script type="text/javascript">
 297             g3 = new Dygraph(
 298               document.getElementById("graphdiv3"),
 299               "temperatures.csv",
 300               {
 301                 rollPeriod: 7,
 302                 showRoller: true
 303               }
 304             );
 305           </script>
 306         </div>
 307       </div>
 308
 309       <p style="clear:both;">A rolling average can be set using the text box in the lower left-hand corner of the graph (the showRoller attribute is what makes this appear). Also note that we've explicitly set the size of the chart div.</p>
 310
 311       <h2>Error Bars</h2>
 312
 313       <p>Another significant feature of the dygraphs library is the ability to display error bars around data series. One standard deviation must be specified for each data point. A <em>&plusmn;n</em> sigma band will be drawn around the data series at that point. If a moving average is being displayed, dygraphs will compute the standard deviation of the average at each point. I.E. <em>&sigma; = sqrt( (&sigma;<sub>1<sup>2</sup></sub> + &sigma;<sub>2<sup>2</sup></sub> + ... + &sigma;<sub>n<sup>2</sup></sub>) / n )</em></p>
 314
 315       <p>Here's a demonstration. There are two data series. One is <code>N(100,10)</code> with a standard deviation of 10 specified at each point. The other is <code>N(80,20)</code> with a standard deviation of 20 specified at each point. The CSV file was generated using Octave and can be viewed at <a href="twonormals.csv">twonormals.csv</a>.</p>
 316
 317       <div class="example" style="clear:both;">
 318         <div class="codeblock" style="float:left;width:400px;">
 319           <h3 style="text-align:center">HTML</h3>
 320           <code>
 321 <pre>
 322 &lt;html&gt;
 323 &lt;head&gt;
 324 &lt;script type=&quot;text/javascript&quot;
 325   src=&quot;combined.js&quot;&gt;&lt;/script&gt;
 326 &lt;/head&gt;
 327 &lt;body&gt;
 328 &lt;div id=&quot;graphdiv4&quot;
 329   style=&quot;width:600px; height:300px;&quot;&gt;&lt;/div&gt;
 330 &lt;script type=&quot;text/javascript&quot;&gt;
 331   g4 = new Dygraph(
 332     document.getElementById(&quot;graphdiv4&quot;),
 333     &quot;twonormals.csv&quot;,
 334     {
 335       rollPeriod: 7,
 336       showRoller: true,
 337       errorBars: true,
 338       valueRange: [50,125]
 339     }
 340   );
 341 &lt;/script&gt;
 342 &lt;/body&gt;
 343 &lt;/html&gt;
 344 </pre>
 345           </code>
 346         </div>
 347         <div class="codeoutput" style="float:left;">
 348           <h3 style="text-align:center">OUTPUT</h3>
 349           <div id="graphdiv4" style="width:600px; height:300px;"></div>
 350           <script type="text/javascript">
 351             g4 = new Dygraph(
 352               document.getElementById("graphdiv4"),
 353               "twonormals.csv",
 354               {
 355                 rollPeriod: 7,
 356                 showRoller: true,
 357                 errorBars: true,
 358                 valueRange: [50,125]
 359               }
 360             );
 361           </script>
 362         </div>
 363       </div>
 364
 365       <p style="clear:both;">Things to note here:</p>
 366
 367       <ul>
 368         <li>The <strong>errorBars</strong> option affects both the interpretation of the CSV file and the display of the graph. When <strong>errorBars</strong> is set to true, each line is interpreted as <em>YYYYMMDD</em>, <em>A</em>, <em>sigma_A</em>, <em>B</em>, <em>sigma_B</em>, &hellip;</li>
 369         <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 370         <li>The averaging visibly affects the error bars. This is most clear if you crank up the rolling period to something like 100 days. For the earliest dates, there won't be 100 data points to average so the signal will be noisier. The error bars get smaller like sqrt(N) going forward in time until there's a full 100 points to average.</li>
 371         <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 372       </ul>
 373
 374       <h2 id="ie">Internet Explorer Compatibility</h2>
 375
 376       <p>The dygraphs library relies heavily on the HTML5 <code>&lt;canvas&gt;</code> tag, which Microsoft Internet Explorer did not traditionally support. To use Microsoft's native canvas implementation in IE9, you need to set an HTML5 doctype on your page:</p>
 377
 378 <pre>
 379 &lt;!DOCTYPE html&gt;
 380 </pre>
 381
 382       <p>When IE9 is in HTML5 mode, dygraphs works just like in other modern browsers.</p>
 383
 384       <p>If you want to support previous versions of Internet Explorer (IE6&ndash;IE8), you'll need to include the <a href="http://code.google.com/p/explorercanvas/">excanvas</a> library, which emulates the <code>&lt;canvas&gt;</code> tag using VML. You can add excanvas by including the following snippet:</p>
 385
 386 <pre>
 387 &lt;!DOCTYPE html&gt;
 388 &lt;html&gt;
 389   &lt;head&gt;
 390     &lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9"&gt;
 391     &lt;!--[if IE]&gt;&lt;script src="path/to/excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 392   &lt;/head&gt;
 393 </pre>
 394
 395 <p>(This is surprisingly tricky because the HTML5 doctype breaks excanvas in IE8. See <a href="https://groups.google.com/group/dygraphs-users/browse_thread/thread/c60709e04bc7fe5f#">this discussion</a> for details.)</p>
 396
 397     <p>While VML emulation sounds like it would be slow, it works well in practice for most charts.</p>
 398
 399     <p>One common gotcha to look out for: make sure you don't have any trailing commas in parameter lists, e.g.</p>
 400
 401 <pre>
 402 new Dygraph(el, data, {
 403   showRoller: true,  // note trailing comma
 404 })</pre>
 405
 406     <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 407
 408     <h2 id="gviz">GViz Data</h2>
 409
 410     <p>The <a
 411       href="http://code.google.com/apis/visualization/documentation/index.html">Google
 412       Visualization API</a> provides a standard interface for describing data.
 413     Once you've specified your data using this API, you can plug in any
 414     GViz-compatible visualization. dygraphs is such a visualization. In
 415     particular, it can be used as a drop-in replacement for the
 416     AnnotatedTimeline visualization used on Google Finance and other sites. To
 417     see how this works, check out the <a href="tests/annotation-gviz.html">gviz
 418       annotation demo.</a></p>
 419
 420     <p>For a simple demonstration of how to use dygraphs a GViz visualization, see <a href="http://danvk.org/dygraphs/tests/gviz.html">http://danvk.org/dygraphs/tests/gviz.html</a>. dygraphs can also be used as a GViz gadget. This allows it to be embedded inside of a Google Spreadsheet. For a demonstration of this, see <a   href="http://spreadsheets.google.com/ccc?key=0Anx1yCqeL8YUdDR1c3pPREhraGhkWmdhaURjOXRncXc&amp;hl=en">this spreadsheet</a>. The URL for the gadget is <code><a href="http://danvk.org/dygraphs/gadget.xml">http://danvk.org/dygraphs/gadget.xml</a></code>.</p>
 421
 422     <p>Here's an example of a published gviz gadget using dygraphs:</p>
 423
 424     <script src="http://spreadsheets.google.com/gpub?url=http%3A%2F%2Fkb8jbn8l90ocl9n4b14jrcvp61ceqis5.spreadsheets.gmodules.com%2Fgadgets%2Fifr%3Fup__table_query_url%3Dhttp%253A%252F%252Fspreadsheets.google.com%252Ftq%253Frange%253DA1%25253AC31%2526headers%253D-1%2526key%253D0Anx1yCqeL8YUdDR1c3pPREhraGhkWmdhaURjOXRncXc%2526gid%253D0%2526pub%253D1%26up__table_query_refresh_interval%3D300%26url%3Dhttp%253A%252F%252Fdanvk.org%252Fdygraphs%252Fgadget.xml%253Fnocache&height=215&width=530"></script>
 425
 426     <h2 id="baseball">Charting Fractions</h2>
 427
 428     <p>Situations often arise where you want to plot fractions, e.g. the fraction of respondents in a poll who said they'd vote for candidate X or the number of hits divided by at bats (baseball's batting average). Fractions require special treatment for two main reasons:</p>
 429
 430     <ul>
 431       <li>The average of <code>a1/b1</code> and <code>a2/b2</code> is <code>(a1+a2)/(b1+b2)</code>, not <code>(a1/b1 + a2/b2)/2</code>.</li>
 432       <li>The normal approximation is not always applicable and more sophisticated confidence intervals (e.g. the <a href="http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval">Wilson confidence interval</a>) must be employed to avoid ratios that exceed 100% or go below 0%.</li>
 433     </ul>
 434
 435     <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 436
 437     <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 438     <div id="baseballdiv" style="width:750px; height:300px;"></div>
 439     <script type="text/javascript">
 440       new Dygraph(
 441         document.getElementById("baseballdiv"),
 442         "suzuki-mariners.txt",
 443         {
 444           fractions: true,
 445           errorBars: true,
 446           showRoller: true,
 447           rollPeriod: 15
 448         }
 449       );
 450     </script>
 451
 452     <p>Command:</p>
 453 <pre>
 454   new Dygraph(
 455     document.getElementById(&quot;baseballdiv&quot;),
 456     &quot;suzuki-mariners.txt&quot;,
 457     {
 458       fractions: true,
 459       errorBars: true,
 460       showRoller: true,
 461       rollPeriod: 15
 462     }
 463   );
 464 </pre>
 465
 466     <p>The <code>fractions</code> option indicates that the values in each column should be parsed as fractions (e.g. "1/2" instead of "0.5"). The <code>errorBars</code> option indicates that we'd like to see a confidence interval around each data point. By default, when <code>fractions</code> is set, you get a Wilson confidence interval. If you look carefully at the chart, you can see that the error bars are asymmetric.</p>
 467
 468     <p>A couple things to notice about this chart:</p>
 469
 470     <ul>
 471       <li>The error bars for Ichiro's batting average are larger than for the Mariners', since he has far fewer at bats than his team.</li>
 472       <li>dygraphs makes it easy to see "batting average over the last 30 games". This is ordinarily quite difficult to compute. It makes it clear where the "hot" and "cold" part of Suzuki's season were.</li>
 473       <li>If you set the averaging period to something large, like 200, you'll see the team's and player's batting average through that game. The final number is the overall batting average for the season.</li>
 474       <li>Where the error bars do not overlap, we can say with 95% confidence that the series differ. There is a better than 95% chance that Ichiro was a better hitter than his team as a whole in 2004, the year he won the batting title.</li>
 475     </ul>
 476
 477     <h2 id="stock">One last demo</h2>
 478
 479     <p>This chart shows monthly closes of the Dow Jones Industrial Average, both in nominal and real (i.e. adjusted for inflation) dollars. The shaded areas show its monthly high and low. CPI values with a base from 1982-84 are used to adjust for inflation.</p>
 480
 481     <div id="dow_chart" style="width:900px; height:350px;"></div>
 482     <p><b>Display: </b>
 483     <input type=checkbox id=0 onClick="stockchange(this)" checked>
 484     <label for="0"> Nominal</label>
 485     <input type=checkbox id=1 onClick="stockchange(this)" checked>
 486     <label for="1"> Real</label>
 487     <input type=checkbox id=ann onClick="annotationschange(this)" checked>
 488     <label for="ann"> Annotations</label>
 489     </p>
 490
 491     <script type="text/javascript">
 492       var stock_annotations = [
 493         {
 494           series: "Real",
 495           x: "1929-08-15",
 496           shortText: "A",
 497           text: "1929 Stock Market Peak"
 498         },
 499         {
 500           series: "Nominal",
 501           x: "1987-08-15",
 502           shortText: "B",
 503           text: "1987 Crash"
 504         },
 505         {
 506           series: "Nominal",
 507           x: "1999-12-15",
 508           shortText: "C",
 509           text: "1999 (.com) Peak"
 510         },
 511         {
 512           series: "Nominal",
 513           x: "2007-10-15",
 514           shortText: "D",
 515           text: "All-Time Market Peak"
 516         }
 517       ];
 518
 519     // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 520       stockchart = new Dygraph(
 521         document.getElementById('dow_chart'),
 522         "dow.txt",
 523         {
 524           showRoller: true,
 525           customBars: true,
 526           labelsKMB: true,
 527           drawCallback: function(g, is_initial) {
 528             if (!is_initial) return;
 529             g.setAnnotations( stock_annotations );
 530           }
 531         }
 532       );
 533
 534       function stockchange(el) {
 535         stockchart.setVisibility(el.id, el.checked);
 536       }
 537
 538       function annotationschange(el) {
 539         if (el.checked) {
 540           stockchart.setAnnotations(stock_annotations);
 541         } else {
 542           stockchart.setAnnotations([]);
 543         }
 544       }
 545     </script>
 546 <!--
 547
 548 Here is a script to regenerate the Dow Jones plot:
 549
 550 # Get unadjusted DJIA data in a nice format:
 551 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 552 sed '1,17d' eq_d_mi_3.csv | cut -d, -f1,6 | perl -pe 's/(\d{4}-\d\d)-\d\d/$1/g' | perl -pe 's/, */\t/' | grep -v 'na' | perl -ne 'chomp; ($m,$v) = split/\t/; $close{$m} = $v; if ($low{$m} == 0 || $v < $low{$m}) { $low{$m}=$v } if ($v > $high{$m}) { $high{$m} = $v } END { for $x(sort keys %close) { print "$x\t$low{$x}\t$close{$x}\t$high{$x}\n" } } ' > monthly-djia.tsv
 553
 554 # Fetch and format the CPI data:
 555 curl 'http://data.bls.gov/PDQ/servlet/SurveyOutputServlet?series_id=CUUR0000SA0&years_option=all_years&periods_option=all_periods&output_type=column&output_format=text&delimiter=comma' > cpi-u.txt
 556 sed '1,/Series Id,Year,/d' cpi-u.txt | sed '/^$/,$d' | cut -d, -f2,3,4 | perl -ne 'print if /,M(0[0-9]|1[012]),/' | perl -pe 's/(\d{4}),M(\d{2}),/$1-$2\t/g' > cpi-u.tsv
 557
 558 # Merge:
 559 join -t'     ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 560 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($m,$cpi,$low,$close,$high) = split /\t/; $cpi /= 100.0; print "$m-15,$low;$close;$high,",($low/$cpi),";",($close/$cpi),";",($high/$cpi),"\n"' annotated-djia.tsv > dow.txt
 561
 562 -->
 563
 564     <h2 id="options">Other Options</h2>
 565
 566     <p>In addition to the options mentioned above (<code>showRoller</code>, <code>rollPeriod</code>, <code>errorBars</code>, <code>valueRange</code>), there are <i>many</i> others.</p>
 567
 568     <p>For a full list, see the <a href="options.html">Dygraphs Options Reference</a> page.</p>
 569
 570     <h2>Common Gotchas</h2>
 571
 572     <p>Here are a few problems that I've frequently run into while using the dygraphs library.</p>
 573
 574     <ul>
 575       <li>If your chart doesn't display, be sure to check your browser's JavaScript error console. dygraphs makes every attempt to log errors and warnings, and these can often guide you in the right direction.</li>
 576       <li>Make sure your CSV files are readable! If your graph isn't showing up, the XMLHttpRequest for the CSV file may be failing. You can determine whether this is the case using tools like <a href="http://www.getfirebug.com/">Firebug</a>.</li>
 577       <li>Make sure your CSV files are in the correct format. They must be of the form <code>YYYYMMDD, series1, series2, </code>&hellip; . And if you set the <code>errorBars</code> property, make sure you alternate data series and standard deviations.</li>
 578       <li>dygraphs are not happy when placed inside a <code>&lt;center&gt;</code> tag. This applies to the CSS <code>text-align</code> property as well. If you want to center a Dygraph, put it inside a table with <code>align = center</code> set.</li>
 579       <li>Don't set the <code>dateWindow</code> property to a date. It expects milliseconds since epoch, which can be obtained from a JavaScript Date object's valueOf method.</li>
 580       <li>Make sure you don't have any trailing commas in your call to the Dygraph constructor or in the options parameter. Firefox, Chrome and Safari ignore these but they can cause a graph to not display in Internet Explorer.</li>
 581     </ul>
 582
 583     <h2 id="gwt">GWT Compatibility</h2>
 584     <p>There is currently no GWT wrapper around Dygraphs, however there is a class that can be used to easily load Dygraphs into the browser.  To use it, include the generated dygraph-gwt.jar file in your classpath and add the following line to your GWT module:</p>
 585
 586 <pre>
 587 &lt;inherits name=&quot;org.danvk.dygraphs&quot;/&gt;
 588 </pre>
 589
 590     <p>Call org.danvk.Dygraphs.install() when your application starts to install the JavaScript code into the browser.  You can use <a href="http://code.google.com/webtoolkit/doc/latest/DevGuideCodingBasicsJSNI.html">JSNI</a> to call Dygraphs from your GWT code, as in the example below.  The example uses the <a href="http://code.google.com/p/gwt-google-apis/wiki/VisualizationGettingStarted">Visualization API for GWT</a> and the <a href="#gviz">Dygraphs GViz API.</a></p>
 591
 592 <pre>
 593   public static native JavaScriptObject drawDygraph(Element element, DataTable dataTable, double minY, double maxY) /*-{
 594     var chart = new $wnd.Dygraph.GVizChart(element);
 595     chart.draw(dataTable,
 596       {
 597         valueRange: [minY, maxY]
 598       });
 599     return chart;
 600   }-*/;
 601 </pre>
 602
 603     <h2 id="policy">Data Policy</h2>
 604     <p>dygraphs is purely client-side JavaScript. It does not send your data to any servers &ndash; the data is processed entirely in the client's browser.</p>
 605
 606     <p style="font-size:0.8em">Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></p>
 607   </div>
 608
 609 </body>
 610 </html>