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  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="#gwt">GWT Compatibility</a></li>
  35         <li><a href="#policy">Data Policy</a></li>
  36         <li><a href="options.html">Options Reference</a></li>
  37         <li><a href="jsdoc/symbols/Dygraph.html">JSDoc Reference</a></li>
  38         <li><a href="data.html">Data Formats</a></li>
  39         <li><a href="annotations.html">Annotations</a></li>
  40       </ul>
  41
  42       <h2>Project</h2>
  43       <ul>
  44         <li><a href="http://github.com/danvk/dygraphs">Source</a></li>
  45         <li><a href="http://code.google.com/p/dygraphs/issues/">Issues</a></li>
  46         <li><a href="http://code.google.com/p/dygraphs/issues/entry">Report Bug</a></li>
  47         <li><a href="changes.html">Contribute a change</a></li>
  48         <li><a href="mailto:dygraphs-users [at] googlegroups.com">Contact</a></li>
  49       </ul>
  50
  51       <h2>Gallery</h2>
  52       <ul>
  53         <li><a href="tests/">(browse demos)</a></li>
  54         <li><a href="tests/demo.html">Basic Demo</a></li>
  55         <li><a href="tests/gviz.html">GViz Demo</a></li>
  56         <li><a href="tests/plotter.html">Equation Plotter</a></li>
  57         <li><a href="tests/perf.html">Performance Test</a></li>
  58         <li><a href="tests/annotation.html">Annotations</a></li>
  59         <li><a href="tests/annotation-gviz.html">Annotations (GViz)</a></li>
  60         <li><a href="tests/fillGraph.html">Filled Chart</a></li>
  61         <li><a href="tests/perf.html">Fractions</a></li>
  62         <li><a href="tests/visibility.html">Visibility</a></li>
  63         <li><a href="tests/label-div.html">Labels in a DIV</a></li>
  64         <li><a href="tests/numeric-axis.html">Numeric Axis</a></li>
  65         <li><a href="tests/draw-points.html">Dotted Points</a></li>
  66         <li><a href="tests/native-format.html">Native Format</a></li>
  67         <li><a href="tests/grid_dot.html">Crazy Styles</a></li>
  68         <li><a href="tests/spacing.html">Tick spacing</a></li>
  69         <li><a href="tests/callback.html">Callbacks</a></li>
  70         <li><a href="tests/crosshair.html">Crosshairs</a></li>
  71         <li><a href="tests/hourly.html">Hourly/Minutely data</a></li>
  72         <li><a href="tests/isolated-points.html">Isolated Points</a></li>
  73         <li><a href="tests/missing-data.html">Missing Data</a></li>
  74         <li><a href="tests/border.html">Bordered chart</a></li>
  75         <li><a href="tests/custom-bars.html">Custom Bars</a></li>
  76         <li><a href="tests/customLabel.html">Custom Label Styles</a></li>
  77         <li><a href="tests/dygraph.html">Minimal Example</a></li>
  78         <li><a href="tests/negative.html">Negative Numbers</a></li>
  79         <li><a href="tests/noise.html">Noisy Data</a></li>
  80         <li><a href="tests/two-series.html">Multiple Series</a></li>
  81         <li><a href="tests/highlighted-region.html">Custom Underlay / background</a></li>
  82         <li><a href="tests/zoom.html">Tests for zoom operations</a></li>
  83         <li><a href="tests/logscale.html">Log scale tests</a></li>
  84       </ul>
  85     </div>
  86
  87     <div id="content">
  88       <h1>dygraphs JavaScript Visualization Library</h1>
  89
  90       <p><a href="http://github.com/danvk/dygraphs">http://github.com/danvk/dygraphs</a></p>
  91       <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>
  92
  93       <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>
  94
  95       <h3 id="demo">A demo is worth a thousand words:</h3>
  96
  97       <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>
  98
  99       <div id="demodiv" style="width:800px; height:320px;"></div>
 100       <script type="text/javascript">
 101         g = new Dygraph(
 102           document.getElementById("demodiv"),
 103           "ny-vs-sf.txt",
 104           {
 105             rollPeriod: 14,
 106             showRoller: true,
 107             customBars: true,
 108             title: 'Daily Temperatures in New York vs. San Francisco',
 109             ylabel: 'Temperature (F)',
 110             legend: 'always',
 111             labelsDivStyles: { 'textAlign': 'right' }
 112           }
 113         );
 114       </script>
 115
 116       <h4>Some things to notice:</h4>
 117       <ul>
 118         <li>There's less seasonal temperature variation in SF than in NY.</li>
 119         <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.</li>
 120         <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.</li>
 121         <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>
 122         <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).</li>
 123         <li>The bands around each point indicate average highs and lows.</li>
 124         <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>
 125       </ul>
 126
 127       <p>dygraphs allows the user to explore the data and discover these facts.</p>
 128
 129       <p>For more demos, browse the dygraph <a href="tests/">tests</a> directory.</p>
 130
 131       <h3>Features</h3>
 132       <p>Some of the features of dygraphs:</p>
 133       <ul>
 134         <li>Plots time series without using an external server or Flash</li>
 135         <li>Works in Internet Explorer (using excanvas)</li>
 136         <li>Lightweight (69kb) and responsive</li>
 137         <li>Displays values on mouseover, making interaction easily discoverable</li>
 138         <li>Supports error bands around data series</li>
 139         <li>Interactive zoom</li>
 140         <li>Displays Annotations on the chart</li>
 141         <li>Adjustable averaging period</li>
 142         <li>Can intelligently chart fractions</li>
 143         <li>Customizable click-through actions</li>
 144         <li>Compatible with the Google Visualization API</li>
 145         <li>Intelligent defaults make it easy to use</li>
 146       </ul>
 147
 148       <h2 id="usage">Usage</h2>
 149
 150       <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>
 151
 152       <p>Here's a basic example to get things started:</p>
 153
 154       <div class="example" style="clear:both;">
 155         <div class="codeblock" style="float:left;width:400px;">
 156           <h3 style="text-align:center">HTML</h3>
 157           <code>
 158   <pre>
 159 &lt;html&gt;
 160 &lt;head&gt;
 161 &lt;script type=&quot;text/javascript&quot;
 162   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 163 &lt;/head&gt;
 164 &lt;body&gt;
 165 &lt;div id=&quot;graphdiv&quot;&gt;&lt;/div&gt;
 166 &lt;script type=&quot;text/javascript&quot;&gt;
 167   g = new Dygraph(
 168
 169     // containing div
 170     document.getElementById(&quot;graphdiv&quot;),
 171
 172     // CSV or path to a CSV file.
 173     &quot;Date,Temperature\n&quot; +
 174     &quot;2008-05-07,75\n&quot; +
 175     &quot;2008-05-08,70\n&quot; +
 176     &quot;2008-05-09,80\n&quot;
 177
 178   );
 179 &lt;/script&gt;
 180 &lt;/body&gt;
 181 &lt;/html&gt;
 182 </pre>
 183           </code>
 184         </div>
 185         <div class="codeoutput" style="float:left;">
 186           <h3 style="text-align:center">OUTPUT</h3>
 187           <div id="graphdiv"></div>
 188           <script type="text/javascript">
 189             g = new Dygraph(
 190
 191               // containing div
 192               document.getElementById("graphdiv"),
 193
 194               // CSV or path to a CSV file.
 195               "Date,Temperature\n" +
 196               "2008-05-07,75\n" +
 197               "2008-05-08,70\n" +
 198               "2008-05-09,80\n"
 199             );
 200           </script>
 201         </div>
 202       </div>
 203
 204       <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>
 205
 206       <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>
 207
 208       <div class="example" style="clear:both;">
 209         <div class="codeblock" style="float:left;width:400px;">
 210           <h3 style="text-align:center">HTML</h3>
 211           <code>
 212 <pre>
 213 &lt;html&gt;
 214 &lt;head&gt;
 215 &lt;script type=&quot;text/javascript&quot;
 216   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 217 &lt;/head&gt;
 218 &lt;body&gt;
 219 &lt;div id=&quot;graphdiv2&quot;
 220   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 221 &lt;script type=&quot;text/javascript&quot;&gt;
 222   g2 = new Dygraph(
 223     document.getElementById(&quot;graphdiv2&quot;),
 224     &quot;temperatures.csv&quot;, // path to CSV file
 225     {}          // options
 226   );
 227 &lt;/script&gt;
 228 &lt;/body&gt;
 229 &lt;/html&gt;
 230 </pre>
 231           </code>
 232         </div>
 233         <div class="codeoutput" style="float:left;">
 234           <h3 style="text-align:center">OUTPUT</h3>
 235           <div id="graphdiv2" style="width:500px; height:300px;"></div>
 236           <script type="text/javascript">
 237             g2 = new Dygraph(
 238               document.getElementById("graphdiv2"),
 239               "temperatures.csv",
 240               {}
 241             );
 242           </script>
 243         </div>
 244       </div>
 245
 246       <p style="clear:both;">The file used is <code><a href="temperatures.csv">temperatures.csv</a></code>.</p>
 247
 248       <p>There are a few things to note here:</p>
 249
 250       <ul>
 251         <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
 252         <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
 253         <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
 254         <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>
 255         <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>
 256         <li>The data is very spiky. A moving average would be easier to interpret.</li>
 257       </ul>
 258
 259       <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>
 260
 261       <div class="example" style="clear:both;">
 262         <div class="codeblock" style="float:left;width:400px;">
 263           <h3 style="text-align:center">HTML</h3>
 264           <code>
 265 <pre>
 266 &lt;html&gt;
 267 &lt;head&gt;
 268 &lt;script type=&quot;text/javascript&quot;
 269   src=&quot;dygraph-combined.js&quot;&gt;&lt;/script&gt;
 270 &lt;/head&gt;
 271 &lt;body&gt;
 272 &lt;div id=&quot;graphdiv3&quot;
 273   style=&quot;width:500px; height:300px;&quot;&gt;&lt;/div&gt;
 274 &lt;script type=&quot;text/javascript&quot;&gt;
 275   g3 = new Dygraph(
 276     document.getElementById(&quot;graphdiv3&quot;),
 277     &quot;temperatures.csv&quot;,
 278     {
 279       rollPeriod: 7,
 280       showRoller: true
 281     }
 282   );
 283 &lt;/script&gt;
 284 &lt;/body&gt;
 285 &lt;/html&gt;
 286 </pre>
 287           </code>
 288         </div>
 289         <div class="codeoutput" style="float:left;">
 290           <h3 style="text-align:center">OUTPUT</h3>
 291           <div id="graphdiv3" style="width:500px; height:300px;"></div>
 292           <script type="text/javascript">
 293             g3 = new Dygraph(
 294               document.getElementById("graphdiv3"),
 295               "temperatures.csv",
 296               {
 297                 rollPeriod: 7,
 298                 showRoller: true
 299               }
 300             );
 301           </script>
 302         </div>
 303       </div>
 304
 305       <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>
 306
 307       <h2>Error Bars</h2>
 308
 309       <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>
 310
 311       <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>
 312
 313       <div class="example" style="clear:both;">
 314         <div class="codeblock" style="float:left;width:400px;">
 315           <h3 style="text-align:center">HTML</h3>
 316           <code>
 317 <pre>
 318 &lt;html&gt;
 319 &lt;head&gt;
 320 &lt;script type=&quot;text/javascript&quot;
 321   src=&quot;combined.js&quot;&gt;&lt;/script&gt;
 322 &lt;/head&gt;
 323 &lt;body&gt;
 324 &lt;div id=&quot;graphdiv4&quot;
 325   style=&quot;width:480px; height:320px;&quot;&gt;&lt;/div&gt;
 326 &lt;script type=&quot;text/javascript&quot;&gt;
 327   g4 = new Dygraph(
 328     document.getElementById(&quot;graphdiv4&quot;),
 329     &quot;twonormals.csv&quot;,
 330     {
 331       rollPeriod: 7,
 332       showRoller: true,
 333       errorBars: true,
 334       valueRange: [50,125]
 335     }
 336   );
 337 &lt;/script&gt;
 338 &lt;/body&gt;
 339 &lt;/html&gt;
 340 </pre>
 341           </code>
 342         </div>
 343         <div class="codeoutput" style="float:left;">
 344           <h3 style="text-align:center">OUTPUT</h3>
 345           <div id="graphdiv4" style="width:480px; height:320px;"></div>
 346           <script type="text/javascript">
 347             g4 = new Dygraph(
 348               document.getElementById("graphdiv4"),
 349               "twonormals.csv",
 350               {
 351                 rollPeriod: 7,
 352                 showRoller: true,
 353                 errorBars: true,
 354                 valueRange: [50,125]
 355               }
 356             );
 357           </script>
 358         </div>
 359       </div>
 360
 361       <p style="clear:both;">Things to note here:</p>
 362
 363       <ul>
 364         <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>
 365         <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 366         <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>
 367         <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 368       </ul>
 369
 370       <h2 id="ie">Internet Explorer Compatibility</h2>
 371
 372       <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>
 373
 374 <pre>
 375 &lt;!DOCTYPE html&gt;
 376 </pre>
 377
 378       <p>When IE9 is in HTML5 mode, dygraphs works just like in other modern browsers.</p>
 379
 380       <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>
 381
 382 <pre>
 383 &lt;!DOCTYPE html&gt;
 384 &lt;html&gt;
 385   &lt;head&gt;
 386     &lt;meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9"&gt;
 387     &lt;!--[if IE]&gt;&lt;script src="path/to/excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 388   &lt;/head&gt;
 389 </pre>
 390
 391 <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>
 392
 393     <p>While VML emulation sounds like it would be slow, it works well in practice for most charts.</p>
 394
 395     <p>One common gotcha to look out for: make sure you don't have any trailing commas in parameter lists, e.g.</p>
 396
 397 <pre>
 398 new Dygraph(el, data, {
 399   showRoller: true,  // note trailing comma
 400 })</pre>
 401
 402     <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 403
 404     <h2 id="gviz">GViz Data</h2>
 405
 406     <p>The <a
 407       href="http://code.google.com/apis/visualization/documentation/index.html">Google
 408       Visualization API</a> provides a standard interface for describing data.
 409     Once you've specified your data using this API, you can plug in any
 410     GViz-compatible visualization. dygraphs is such a visualization. In
 411     particular, it can be used as a drop-in replacement for the
 412     AnnotatedTimeline visualization used on Google Finance and other sites. To
 413     see how this works, check out the <a href="tests/annotation-gviz.html">gviz
 414       annotation demo.</a></p>
 415
 416     <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>
 417
 418     <p>Here's an example of a published gviz gadget using dygraphs:</p>
 419
 420     <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>
 421
 422     <h2 id="baseball">Charting Fractions</h2>
 423
 424     <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>
 425
 426     <ul>
 427       <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>
 428       <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>
 429     </ul>
 430
 431     <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 432
 433     <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 434     <div id="baseballdiv" style="width:750px; height:300px;"></div>
 435     <script type="text/javascript">
 436       new Dygraph(
 437         document.getElementById("baseballdiv"),
 438         "suzuki-mariners.txt",
 439         {
 440           fractions: true,
 441           errorBars: true,
 442           showRoller: true,
 443           rollPeriod: 15
 444         }
 445       );
 446     </script>
 447
 448     <p>Command:</p>
 449 <pre>
 450   new Dygraph(
 451     document.getElementById(&quot;baseballdiv&quot;),
 452     &quot;suzuki-mariners.txt&quot;,
 453     {
 454       fractions: true,
 455       errorBars: true,
 456       showRoller: true,
 457       rollPeriod: 15
 458     }
 459   );
 460 </pre>
 461
 462     <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>
 463
 464     <p>A couple things to notice about this chart:</p>
 465
 466     <ul>
 467       <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>
 468       <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>
 469       <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>
 470       <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>
 471     </ul>
 472
 473     <h2 id="stock">One last demo</h2>
 474
 475     <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>
 476
 477     <div id="dow_chart" style="width:750px; height:350px;"></div>
 478     <p><b>Display: </b>
 479     <input type=checkbox id=0 onClick="stockchange(this)" checked>
 480     <label for="0"> Nominal</label>
 481     <input type=checkbox id=1 onClick="stockchange(this)" checked>
 482     <label for="1"> Real</label>
 483     <input type=checkbox id=ann onClick="annotationschange(this)" checked>
 484     <label for="ann"> Annotations</label>
 485     </p>
 486
 487     <script type="text/javascript">
 488       var stock_annotations = [
 489         {
 490           series: "Real",
 491           x: "1929-08-15",
 492           shortText: "A",
 493           text: "1929 Stock Market Peak"
 494         },
 495         {
 496           series: "Nominal",
 497           x: "1987-08-15",
 498           shortText: "B",
 499           text: "1987 Crash"
 500         },
 501         {
 502           series: "Nominal",
 503           x: "1999-12-15",
 504           shortText: "C",
 505           text: "1999 (.com) Peak"
 506         },
 507         {
 508           series: "Nominal",
 509           x: "2007-10-15",
 510           shortText: "D",
 511           text: "All-Time Market Peak"
 512         }
 513       ];
 514
 515     // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 516       stockchart = new Dygraph(
 517         document.getElementById('dow_chart'),
 518         "dow.txt",
 519         {
 520           showRoller: true,
 521           customBars: true,
 522           labelsKMB: true,
 523           drawCallback: function(g, is_initial) {
 524             if (!is_initial) return;
 525             g.setAnnotations( stock_annotations );
 526           }
 527         }
 528       );
 529
 530       function stockchange(el) {
 531         stockchart.setVisibility(el.id, el.checked);
 532       }
 533
 534       function annotationschange(el) {
 535         if (el.checked) {
 536           stockchart.setAnnotations(stock_annotations);
 537         } else {
 538           stockchart.setAnnotations([]);
 539         }
 540       }
 541     </script>
 542 <!--
 543
 544 Here is a script to regenerate the Dow Jones plot:
 545
 546 # Get unadjusted DJIA data in a nice format:
 547 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 548 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
 549
 550 # Fetch and format the CPI data:
 551 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
 552 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-$2\t/g' > cpi-u.tsv
 553
 554 # Merge:
 555 join -t'     ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 556 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 557
 558 -->
 559
 560     <h2 id="options">Other Options</h2>
 561
 562     <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>
 563
 564     <p>For a full list, see the <a href="options.html">Dygraphs Options Reference</a> page.</p>
 565
 566     <h2>Common Gotchas</h2>
 567
 568     <p>Here are a few problems that I've frequently run into while using the dygraphs library.</p>
 569
 570     <ul>
 571       <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>
 572       <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>
 573       <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>
 574       <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>
 575       <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>
 576       <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>
 577     </ul>
 578
 579     <h2 id="gwt">GWT Compatibility</h2>
 580     <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>
 581
 582 <pre>
 583 &lt;inherits name=&quot;org.danvk.dygraphs&quot;/&gt;
 584 </pre>
 585
 586     <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>
 587
 588 <pre>
 589 public static native JavaScriptObject drawDygraph(
 590     Element element, DataTable dataTable, double minY, double maxY) /*-{
 591   var chart = new $wnd.Dygraph.GVizChart(element);
 592   chart.draw(dataTable,
 593     {
 594       valueRange: [minY, maxY]
 595     });
 596   return chart;
 597 }-*/;
 598 </pre>
 599
 600     <h2 id="policy">Data Policy</h2>
 601     <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>
 602
 603     <p style="font-size:0.8em">Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></p>
 604   </div>
 605
 606 </body>
 607 </html>