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="demodiv" style="width:800px; height:320px;"></div>
 103       <script type="text/javascript">
 104         g = new Dygraph(
 105           document.getElementById("demodiv"),
 106           "ny-vs-sf.txt",
 107           {
 108             rollPeriod: 14,
 109             showRoller: true,
 110             customBars: true,
 111             title: 'Daily Temperatures in New York vs. San Francisco',
 112             ylabel: 'Temperature (F)',
 113             legend: 'always',
 114             labelsDivStyles: { 'textAlign': 'right' }
 115           }
 116         );
 117       </script>
 118
 119       <h4>Some things to notice:</h4>
 120       <ul>
 121         <li>There's less seasonal temperature variation in SF than in NY.</li>
 122         <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.</li>
 123         <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.</li>
 124         <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>
 125         <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).</li>
 126         <li>The bands around each point indicate average highs and lows.</li>
 127         <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>
 128       </ul>
 129
 130       <p>dygraphs allows the user to explore the data and discover these facts.</p>
 131
 132       <p>For more demos, browse the dygraph <a href="tests/">tests</a> directory.</p>
 133
 134       <h3>Features</h3>
 135       <p>Some of the features of dygraphs:</p>
 136       <ul>
 137         <li>Plots time series without using an external server or Flash</li>
 138         <li>Works in Internet Explorer (using excanvas)</li>
 139         <li>Lightweight (69kb) and responsive</li>
 140         <li>Displays values on mouseover, making interaction easily discoverable</li>
 141         <li>Supports error bands around data series</li>
 142         <li>Interactive zoom</li>
 143         <li>Displays Annotations on the chart</li>
 144         <li>Adjustable averaging period</li>
 145         <li>Can intelligently chart fractions</li>
 146         <li>Customizable click-through actions</li>
 147         <li>Compatible with the Google Visualization API</li>
 148         <li>Intelligent defaults make it easy to use</li>
 149       </ul>
 150
 151       <h2 id="usage">Usage</h2>
 152
 153       <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>
 154
 155       <p>Here's a basic example to get things started:</p>
 156
 157       <div class="example" style="clear:both;">
 158         <div class="codeblock" style="float:left;width:400px;">
 159           <h3 style="text-align:center">HTML</h3>
 160           <code>
 161   <pre>
 162 &lt;html&gt;
 163 &lt;head&gt;
 164 &lt;script type=&quot;text/javascript&quot;
 165   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 166 &lt;/head&gt;
 167 &lt;body&gt;
 168 &lt;div id=&quot;graphdiv&quot;&gt;&lt;/div&gt;
 169 &lt;script type=&quot;text/javascript&quot;&gt;
 170   g = new Dygraph(
 171
 172     // containing div
 173     document.getElementById(&quot;graphdiv&quot;),
 174
 175     // CSV or path to a CSV file.
 176     &quot;Date,Temperature\n&quot; +
 177     &quot;2008-05-07,75\n&quot; +
 178     &quot;2008-05-08,70\n&quot; +
 179     &quot;2008-05-09,80\n&quot;
 180
 181   );
 182 &lt;/script&gt;
 183 &lt;/body&gt;
 184 &lt;/html&gt;
 185 </pre>
 186           </code>
 187         </div>
 188         <div class="codeoutput" style="float:left;">
 189           <h3 style="text-align:center">OUTPUT</h3>
 190           <div id="graphdiv"></div>
 191           <script type="text/javascript">
 192             g = new Dygraph(
 193
 194               // containing div
 195               document.getElementById("graphdiv"),
 196
 197               // CSV or path to a CSV file.
 198               "Date,Temperature\n" +
 199               "2008-05-07,75\n" +
 200               "2008-05-08,70\n" +
 201               "2008-05-09,80\n"
 202             );
 203           </script>
 204         </div>
 205       </div>
 206
 207       <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>
 208
 209       <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>
 210
 211       <div class="example" style="clear:both;">
 212         <div class="codeblock" style="float:left;width:400px;">
 213           <h3 style="text-align:center">HTML</h3>
 214           <code>
 215 <pre>
 216 &lt;html&gt;
 217 &lt;head&gt;
 218 &lt;script type=&quot;text/javascript&quot;
 219   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 220 &lt;/head&gt;
 221 &lt;body&gt;
 222 &lt;div id=&quot;graphdiv2&quot;
 223   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 224 &lt;script type=&quot;text/javascript&quot;&gt;
 225   g2 = new Dygraph(
 226     document.getElementById(&quot;graphdiv2&quot;),
 227     &quot;temperatures.csv&quot;, // path to CSV file
 228     {}          // options
 229   );
 230 &lt;/script&gt;
 231 &lt;/body&gt;
 232 &lt;/html&gt;
 233 </pre>
 234           </code>
 235         </div>
 236         <div class="codeoutput" style="float:left;">
 237           <h3 style="text-align:center">OUTPUT</h3>
 238           <div id="graphdiv2" style="width:500px; height:300px;"></div>
 239           <script type="text/javascript">
 240             g2 = new Dygraph(
 241               document.getElementById("graphdiv2"),
 242               "temperatures.csv",
 243               {}
 244             );
 245           </script>
 246         </div>
 247       </div>
 248
 249       <p style="clear:both;">The file used is <code><a href="temperatures.csv">temperatures.csv</a></code>.</p>
 250
 251       <p>There are a few things to note here:</p>
 252
 253       <ul>
 254         <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
 255         <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
 256         <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
 257         <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>
 258         <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>
 259         <li>The data is very spiky. A moving average would be easier to interpret.</li>
 260       </ul>
 261
 262       <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>
 263
 264       <div class="example" style="clear:both;">
 265         <div class="codeblock" style="float:left;width:400px;">
 266           <h3 style="text-align:center">HTML</h3>
 267           <code>
 268 <pre>
 269 &lt;html&gt;
 270 &lt;head&gt;
 271 &lt;script type=&quot;text/javascript&quot;
 272   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 273 &lt;/head&gt;
 274 &lt;body&gt;
 275 &lt;div id=&quot;graphdiv3&quot;
 276   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 277 &lt;script type=&quot;text/javascript&quot;&gt;
 278   g3 = new Dygraph(
 279     document.getElementById(&quot;graphdiv3&quot;),
 280     &quot;temperatures.csv&quot;,
 281     {
 282       rollPeriod: 7,
 283       showRoller: true
 284     }
 285   );
 286 &lt;/script&gt;
 287 &lt;/body&gt;
 288 &lt;/html&gt;
 289 </pre>
 290           </code>
 291         </div>
 292         <div class="codeoutput" style="float:left;">
 293           <h3 style="text-align:center">OUTPUT</h3>
 294           <div id="graphdiv3" style="width:500px; height:300px;"></div>
 295           <script type="text/javascript">
 296             g3 = new Dygraph(
 297               document.getElementById("graphdiv3"),
 298               "temperatures.csv",
 299               {
 300                 rollPeriod: 7,
 301                 showRoller: true
 302               }
 303             );
 304           </script>
 305         </div>
 306       </div>
 307
 308       <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>
 309
 310       <h2>Error Bars</h2>
 311
 312       <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>
 313
 314       <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>
 315
 316       <div class="example" style="clear:both;">
 317         <div class="codeblock" style="float:left;width:400px;">
 318           <h3 style="text-align:center">HTML</h3>
 319           <code>
 320 <pre>
 321 &lt;html&gt;
 322 &lt;head&gt;
 323 &lt;script type=&quot;text/javascript&quot;
 324   src=&quot;combined.js&quot;&gt;&lt;/script&gt;
 325 &lt;/head&gt;
 326 &lt;body&gt;
 327 &lt;div id=&quot;graphdiv4&quot;
 328   style=&quot;width:600px; height:300px;&quot;&gt;&lt;/div&gt;
 329 &lt;script type=&quot;text/javascript&quot;&gt;
 330   g4 = new Dygraph(
 331     document.getElementById(&quot;graphdiv4&quot;),
 332     &quot;twonormals.csv&quot;,
 333     {
 334       rollPeriod: 7,
 335       showRoller: true,
 336       errorBars: true,
 337       valueRange: [50,125]
 338     }
 339   );
 340 &lt;/script&gt;
 341 &lt;/body&gt;
 342 &lt;/html&gt;
 343 </pre>
 344           </code>
 345         </div>
 346         <div class="codeoutput" style="float:left;">
 347           <h3 style="text-align:center">OUTPUT</h3>
 348           <div id="graphdiv4" style="width:600px; height:300px;"></div>
 349           <script type="text/javascript">
 350             g4 = new Dygraph(
 351               document.getElementById("graphdiv4"),
 352               "twonormals.csv",
 353               {
 354                 rollPeriod: 7,
 355                 showRoller: true,
 356                 errorBars: true,
 357                 valueRange: [50,125]
 358               }
 359             );
 360           </script>
 361         </div>
 362       </div>
 363
 364       <p style="clear:both;">Things to note here:</p>
 365
 366       <ul>
 367         <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>
 368         <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 369         <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>
 370         <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 371       </ul>
 372
 373       <h2 id="ie">Internet Explorer Compatibility</h2>
 374
 375       <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>
 376
 377 <pre>
 378 &lt;!DOCTYPE html&gt;
 379 </pre>
 380
 381       <p>When IE9 is in HTML5 mode, dygraphs works just like in other modern browsers.</p>
 382
 383       <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>
 384
 385 <pre>
 386 &lt;!DOCTYPE html&gt;
 387 &lt;html&gt;
 388   &lt;head&gt;
 389     &lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9"&gt;
 390     &lt;!--[if IE]&gt;&lt;script src="path/to/excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 391   &lt;/head&gt;
 392 </pre>
 393
 394 <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>
 395
 396     <p>While VML emulation sounds like it would be slow, it works well in practice for most charts.</p>
 397
 398     <p>One common gotcha to look out for: make sure you don't have any trailing commas in parameter lists, e.g.</p>
 399
 400 <pre>
 401 new Dygraph(el, data, {
 402   showRoller: true,  // note trailing comma
 403 })</pre>
 404
 405     <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 406
 407     <h2 id="gviz">GViz Data</h2>
 408
 409     <p>The <a
 410       href="http://code.google.com/apis/visualization/documentation/index.html">Google
 411       Visualization API</a> provides a standard interface for describing data.
 412     Once you've specified your data using this API, you can plug in any
 413     GViz-compatible visualization. dygraphs is such a visualization. In
 414     particular, it can be used as a drop-in replacement for the
 415     AnnotatedTimeline visualization used on Google Finance and other sites. To
 416     see how this works, check out the <a href="tests/annotation-gviz.html">gviz
 417       annotation demo.</a></p>
 418
 419     <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>
 420
 421     <p>Here's an example of a published gviz gadget using dygraphs:</p>
 422
 423     <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>
 424
 425     <h2 id="baseball">Charting Fractions</h2>
 426
 427     <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>
 428
 429     <ul>
 430       <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>
 431       <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>
 432     </ul>
 433
 434     <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 435
 436     <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 437     <div id="baseballdiv" style="width:750px; height:300px;"></div>
 438     <script type="text/javascript">
 439       new Dygraph(
 440         document.getElementById("baseballdiv"),
 441         "suzuki-mariners.txt",
 442         {
 443           fractions: true,
 444           errorBars: true,
 445           showRoller: true,
 446           rollPeriod: 15
 447         }
 448       );
 449     </script>
 450
 451     <p>Command:</p>
 452 <pre>
 453   new Dygraph(
 454     document.getElementById(&quot;baseballdiv&quot;),
 455     &quot;suzuki-mariners.txt&quot;,
 456     {
 457       fractions: true,
 458       errorBars: true,
 459       showRoller: true,
 460       rollPeriod: 15
 461     }
 462   );
 463 </pre>
 464
 465     <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>
 466
 467     <p>A couple things to notice about this chart:</p>
 468
 469     <ul>
 470       <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>
 471       <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>
 472       <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>
 473       <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>
 474     </ul>
 475
 476     <h2 id="stock">One last demo</h2>
 477
 478     <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>
 479
 480     <div id="dow_chart" style="width:900px; height:350px;"></div>
 481     <p><b>Display: </b>
 482     <input type=checkbox id=0 onClick="stockchange(this)" checked>
 483     <label for="0"> Nominal</label>
 484     <input type=checkbox id=1 onClick="stockchange(this)" checked>
 485     <label for="1"> Real</label>
 486     <input type=checkbox id=ann onClick="annotationschange(this)" checked>
 487     <label for="ann"> Annotations</label>
 488     </p>
 489
 490     <script type="text/javascript">
 491       var stock_annotations = [
 492         {
 493           series: "Real",
 494           x: "1929-08-15",
 495           shortText: "A",
 496           text: "1929 Stock Market Peak"
 497         },
 498         {
 499           series: "Nominal",
 500           x: "1987-08-15",
 501           shortText: "B",
 502           text: "1987 Crash"
 503         },
 504         {
 505           series: "Nominal",
 506           x: "1999-12-15",
 507           shortText: "C",
 508           text: "1999 (.com) Peak"
 509         },
 510         {
 511           series: "Nominal",
 512           x: "2007-10-15",
 513           shortText: "D",
 514           text: "All-Time Market Peak"
 515         }
 516       ];
 517
 518     // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 519       stockchart = new Dygraph(
 520         document.getElementById('dow_chart'),
 521         "dow.txt",
 522         {
 523           showRoller: true,
 524           customBars: true,
 525           labelsKMB: true,
 526           drawCallback: function(g, is_initial) {
 527             if (!is_initial) return;
 528             g.setAnnotations( stock_annotations );
 529           }
 530         }
 531       );
 532
 533       function stockchange(el) {
 534         stockchart.setVisibility(el.id, el.checked);
 535       }
 536
 537       function annotationschange(el) {
 538         if (el.checked) {
 539           stockchart.setAnnotations(stock_annotations);
 540         } else {
 541           stockchart.setAnnotations([]);
 542         }
 543       }
 544     </script>
 545 <!--
 546
 547 Here is a script to regenerate the Dow Jones plot:
 548
 549 # Get unadjusted DJIA data in a nice format:
 550 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 551 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
 552
 553 # Fetch and format the CPI data:
 554 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
 555 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-$2\t/g' > cpi-u.tsv
 556
 557 # Merge:
 558 join -t'     ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 559 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 560
 561 -->
 562
 563     <h2 id="options">Other Options</h2>
 564
 565     <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>
 566
 567     <p>For a full list, see the <a href="options.html">Dygraphs Options Reference</a> page.</p>
 568
 569     <h2>Common Gotchas</h2>
 570
 571     <p>Here are a few problems that I've frequently run into while using the dygraphs library.</p>
 572
 573     <ul>
 574       <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>
 575       <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>
 576       <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>
 577       <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>
 578       <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>
 579       <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>
 580     </ul>
 581
 582     <h2 id="gwt">GWT Compatibility</h2>
 583     <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>
 584
 585 <pre>
 586 &lt;inherits name=&quot;org.danvk.dygraphs&quot;/&gt;
 587 </pre>
 588
 589     <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>
 590
 591 <pre>
 592   public static native JavaScriptObject drawDygraph(Element element, DataTable dataTable, double minY, double maxY) /*-{
 593     var chart = new $wnd.Dygraph.GVizChart(element);
 594     chart.draw(dataTable,
 595       {
 596         valueRange: [minY, maxY]
 597       });
 598     return chart;
 599   }-*/;
 600 </pre>
 601
 602     <h2 id="policy">Data Policy</h2>
 603     <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>
 604
 605     <p style="font-size:0.8em">Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></p>
 606   </div>
 607
 608 </body>
 609 </html>