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  54 <ul>
  55 <li><b>Documentation</b>
  56   <ul>
  57   <li><a href="#demo">Demo</a>
  58   <li><a href="#usage">Usage</a>
  59   <li><a href="#ie">IE Compatibility</a>
  60   <li><a href="#gviz">GViz Data</a>
  61   <li><a href="#baseball">Baseball chart</a>
  62   <li><a href="#stock">Stock chart</a>
  63   <li><a href="#options">Options Reference</a>
  64   <li><a href="#policy">Data Policy</a>
  65   </ul>
  66
  67 <li><b>Project</b>
  68   <ul>
  69   <li><a href="http://github.com/danvk/dygraphs">Source</a>
  70   <li><a href="http://code.google.com/p/dygraphs/issues/">Issues</a>
  71   <li><a href="http://code.google.com/p/dygraphs/issues/entry">Report Bug</a>
  72   <li><a href="mailto:danvdk [at] gmail">Contact</a>
  73   </ul>
  74
  75
  76 <li><b>Gallery</b>
  77   <ul>
  78   <li><a href="tests/demo.html">Basic Demo</a>
  79   <li><a href="tests/gviz.html">GViz Demo</a>
  80   <li><a href="tests/plotter.html">Equation Plotter</a>
  81   <li><a href="tests/perf.html">Performance Test</a>
  82   <li><a href="tests/perf.html">Fractions</a>
  83
  84   <li><a href="tests/label-div.html">Labels in a DIV</a>
  85   <li><a href="tests/numeric-axis.html">Numeric Axis</a>
  86   <li><a href="tests/draw-points.html">Dotted Points</a>
  87
  88   <li><a href="tests/native-format.html">Native Format</a>
  89   <li><a href="tests/grid_dot.html">Crazy Styles</a>
  90   <li><a href="tests/spacing.html">Tick spacing</a>
  91   <li><a href="tests/callback.html">Callbacks</a>
  92   <li><a href="tests/crosshair.html">Crosshairs</a>
  93   <li><a href="tests/hourly.html">Hourly/Minutely data</a>
  94
  95   <li><a href="tests/isolated-points.html">Isolated Points</a>
  96   <li><a href="tests/missing-data.html">Missing Data</a>
  97
  98   <li><a href="tests/border.html">Bordered chart</a>
  99   <li><a href="tests/custom-bars.html">Custom Bars</a>
 100   <li><a href="tests/customLabel.html">Custom Label Styles</a>
 101   <li><a href="tests/dygraph.html">Minimal Example</a>
 102   <li><a href="tests/negative.html">Negative Numbers</a>
 103   <li><a href="tests/noise.html">Noisy Data</a>
 104   <li><a href="tests/two-series.html">Multiple Series</a>
 105   </ul>
 106 </ul>
 107 </div>
 108
 109 <div id="content">
 110 <p><span style="font-size:28pt;">dygraphs JavaScript Visualization Library</span><br/>
 111 <a href="http://github.com/danvk/dygraphs">http://github.com/danvk/dygraphs</a><br/>
 112 See <a href="tests/">gallery</a> and <a href="http://code.google.com/p/dygraphs/issues/">open issues</a></p>
 113
 114 <p>The dygraphs JavaScript library 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>
 115
 116 <a name="demo">
 117 <p>A demo is worth a thousand words:</p>
 118
 119 <p><font size=-1>(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.)</font></p>
 120 <div id="title" style="width:800px; text-align:center; font-weight: bold; font-size: 125%;">Temperatures in New York vs. San Francisco</div>
 121 <div id="demodiv" style="width:800px; height:320px;"></div>
 122 <script type="text/javascript">
 123   g = new Dygraph(
 124           document.getElementById("demodiv"),
 125           "ny-vs-sf.txt",
 126           {
 127             rollPeriod: 14,
 128             showRoller: true,
 129             customBars: true,
 130             yAxisLabelWidth: 30
 131           }
 132       );
 133 </script>
 134
 135 <p>Some things to notice:</p>
 136 <ul>
 137 <li>There's less seasonal temperature variation in SF than in NY.
 138 <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.
 139 <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.
 140 <li>Using a 14-day moving average makes it clearer. A 100-day rolling period averages out nearly all the specifics from the data.
 141 <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).
 142 <li>The bands around each point indicate average highs and lows.
 143 <li>There is a <i>lot</i> 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.
 144 </ul>
 145
 146 <p>dygraphs allows the user to explore the data and discover these facts.</p>
 147
 148 <p>For more demos, browse the dygraph <a href="tests/">tests</a> directory.</p>
 149
 150 <h3>Features</h3>
 151 <p>Some of the features of dygraphs:</p>
 152 <ul>
 153   <li>Plots time series without using an external server or Flash</li>
 154   <li>Works in Internet Explorer (using excanvas)</li>
 155   <li>Lightweight (45kb) and responsive</li>
 156   <li>Displays values on mouseover (this makes it easily discoverable)</li>
 157   <li>Supports error bands around data series</li>
 158   <li>Interactive zoom</li>
 159   <li>Adjustable averaging period</li>
 160   <li>Can intelligently chart fractions</li>
 161   <li>Customizable click-through actions</li>
 162   <li>Compatible with the Google Visualization API</li>
 163   <li>Intelligent defaults make it easy to use</li>
 164 </ul>
 165
 166 <a name="usage"><h2>Usage</h2>
 167
 168 <p>To use dygraphs, include the <code>dygraph-combined.js</code> JavaScript file and instantiate a <code>Dygraph</code> object.</p>
 169
 170 <p>Here's a basic example to get things started:</p>
 171
 172 <table>
 173   <tr><th>HTML</th>
 174       <td rowspan=2><img src=arrow.gif /></td>
 175       <th>Output</th></tr>
 176 <tr>
 177 <td valign=top><pre>
 178 &lt;html&gt;
 179 &lt;head&gt;
 180 &lt;script type="text/javascript"
 181   src="dygraph-combined.js"&gt;&lt;/script&gt;
 182 &lt;/head&gt;
 183 &lt;body&gt;
 184 &lt;div id="graphdiv"&gt;&lt;/div&gt;
 185 &lt;script type="text/javascript"&gt;
 186   g = new Dygraph(
 187         // containing div
 188         document.getElementById("graphdiv"),
 189         // CSV or path to a CSV file.
 190         "Date,Temperature\n" +
 191         "2008-05-07,75\n" +
 192         "2008-05-08,70\n" +
 193         "2008-05-09,80\n"
 194       );
 195 &lt;/script&gt;
 196 &lt;/body&gt;
 197 &lt;/html&gt;
 198 </pre>
 199 </td><td valign=top>
 200   <div id="graphdiv"></div>
 201 </td></tr></table>
 202
 203 <script type="text/javascript">
 204   g1 = new Dygraph(
 205        document.getElementById("graphdiv"),  // containing div
 206        "Date,Temperature\n" +                // CSV or path to a CSV file.
 207        "2008-05-07,75\n" +
 208        "2008-05-08,70\n" +
 209        "2008-05-09,80\n"
 210      );
 211 </script>
 212
 213 <p>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 the its container to a reasonable default, calculates appropriate axis ranges and tick marks and draws the graph.</p>
 214
 215 <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&monthend=12&yearend=2007&req_city=NA&req_state=NA&req_statename=NA">Weather Underground</a>)</p>
 216
 217 <table>
 218   <tr><th>HTML</th>
 219       <td rowspan=2><img src=arrow.gif /></td>
 220       <th>Output</th></tr>
 221 <tr>
 222 <td valign=top><pre>
 223 &lt;html&gt;
 224 &lt;head&gt;
 225 &lt;script type="text/javascript"
 226   src="dygraph-combined.js"&gt;&lt;/script&gt;
 227 &lt;/head&gt;
 228 &lt;body&gt;
 229 &lt;div id="graphdiv"
 230   style="width:500px; height:300px;"&gt;&lt;/div&gt;
 231 &lt;script type="text/javascript"&gt;
 232   new Dygraph(
 233     document.getElementById("graphdiv"),
 234     "temperatures.csv",  // path to CSV file
 235     {}                   // options
 236   );
 237 &lt;/script&gt;
 238 &lt;/body&gt;
 239 &lt;/html&gt;
 240 </pre>
 241 </td><td valign=top>
 242   <div id="graphdiv2" style="width:500px; height:300px;"></div>
 243 </td></tr></table>
 244
 245 <script type="text/javascript">
 246   g2 = new Dygraph(
 247         document.getElementById("graphdiv2"),
 248         "temperatures.csv", {}
 249       );
 250 </script>
 251
 252 <p>Click <a href="temperatures.csv">here</a> to view the <code>temperatures.csv</code> file. 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 <table>
 266   <tr><th>HTML</th>
 267       <td rowspan=2><img src=arrow.gif /></td>
 268       <th>Output</th></tr>
 269 <tr>
 270 <td valign=top><pre>
 271 &lt;html&gt;
 272 &lt;head&gt;
 273 &lt;script type="text/javascript"
 274   src="dygraph-combined.js"&gt;&lt;/script&gt;
 275 &lt;/head&gt;
 276 &lt;body&gt;
 277 &lt;div id="graphdiv"
 278   style="width:500px; height:300px;"&gt;&lt;/div&gt;
 279 &lt;script type="text/javascript"&gt;
 280   g = new Dygraph(
 281         document.getElementById("graphdiv"),
 282         "temperatures.csv",
 283         { rollPeriod: 7,
 284           showRoller: true,
 285         }
 286       );
 287 &lt;/script&gt;
 288 &lt;/body&gt;
 289 &lt;/html&gt;
 290 </pre>
 291 </td><td valign=top>
 292   <div id="graphdiv3" style="width:500px; height:300px;"></div>
 293 </td></tr></table>
 294
 295 <script type="text/javascript">
 296   g3 = new Dygraph(
 297         document.getElementById("graphdiv3"),
 298         "temperatures.csv",
 299         { rollPeriod: 7,
 300           showRoller: true });
 301 </script>
 302
 303 <p>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>
 304
 305 <h2>Error Bars</h2>
 306 <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 +/-<i>n</i> 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. <i>&sigma;</i> = sqrt((<i>&sigma;_1</i>^2 + <i>&sigma;_2</i>^2 + ... + <i>&sigma;_n</i>^2)/<i>n</i>))</p>
 307
 308 <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 <a href="twonormals.csv">here</a>.</p>
 309
 310 <table>
 311   <tr><th>HTML</th>
 312       <td rowspan=2><img src=arrow.gif /></td>
 313       <th>Output</th></tr>
 314 <tr>
 315 <td valign=top><pre>
 316 &lt;html&gt;
 317 &lt;head&gt;
 318 &lt;script type="text/javascript"
 319   src="combined.js"&gt;&lt;/script&gt;
 320 &lt;/head&gt;
 321 &lt;body&gt;
 322 &lt;div id="graphdiv"
 323  style="width:600px; height:300px;"
 324  &gt;&lt;/div&gt;
 325 &lt;script type="text/javascript"&gt;
 326 $ = document.getElementById;
 327 g = new Dygraph(
 328   $("graphdiv"),
 329   "twonormals.csv",
 330   { rollPeriod: 7,
 331     showRoller: true,
 332     errorBars: true,
 333     valueRange: [50,125]
 334   }
 335 );
 336 &lt;/script&gt;
 337 &lt;/body&gt;
 338 &lt;/html&gt;
 339 </pre>
 340 </td><td valign=top>
 341   <div id="graphdiv4" style="width:600px; height:300px;"></div>
 342 </td></tr></table>
 343
 344 <script type="text/javascript">
 345 $ = document.getElementById;
 346 new Dygraph(
 347   document.getElementById("graphdiv4"),
 348   "twonormals.csv",
 349   { rollPeriod: 14,
 350     showRoller: true,
 351     errorBars: true,
 352     valueRange: [50, 125]
 353   }
 354 );
 355 </script>
 356
 357 <p>Things to note here:</p>
 358 <ul>
 359   <li>The <b>errorBars</b> option affects both the interpretation of the CSV file and the display of the graph. When <b>errorBars</b> is set to true, each line is interpreted as <i>YYYYMMDD</i>,<i>A</i>,<i>sigma_A</i>,<i>B</i>,<i>sigma_B</i>,...</li>
 360   <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 361   <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>
 362   <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 363 </ul>
 364
 365 <a name="ie"><h2>Internet Explorer Compatibility</h2>
 366
 367 <p>The dygraphs library relies heavily on HTML's &lt;canvas&gt; tag, which
 368 Microsoft Internet Explorer does not support. Fortunately, some clever engineers
 369 created the <a href="http://code.google.com/p/explorercanvas/">excanvas</a>
 370 library, which imlements the &lt;canvas&gt; tag in IE using VML.</p>
 371
 372 <p>You can add IE support to any page using dygraphs by including the following
 373 in your page:</p>
 374
 375 <pre>
 376 &lt;head&gt;
 377 &lt;!--[if IE]&gt;&lt;script src="excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 378 &lt;/head&gt;
 379 </pre>
 380
 381 <p>This works quite well in practice. Charts are responsive, even under VML
 382 emulation.</p>
 383
 384 <p>One common gotcha to look out for: make sure you don't have any trailing
 385 commas in parameter lists, e.g.</p>
 386
 387 <pre>new Dygraph(el, data, {
 388   showRoller:true,  // &lt;-- note trailing comma
 389 })</pre>
 390
 391 <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 392
 393 <a name="gviz"><h2>GViz Data</h2>
 394 <p>The <a
 395   href="http://code.google.com/apis/visualization/documentation/index.html">Google
 396   Visualization API</a> provides a standard interface for describing data. Once
 397 you've specified your data using this API, you can plug in any GViz-compatible
 398 visualization. dygraphs is such a visualization.</p>
 399
 400 <p>For a simple demonstration of how to use dygraphs a GViz visualization, see
 401 <a href="http://danvk.org/dygraphs/tests/gviz.html">this page</a>. dygraphs can
 402 also be used as a GViz gadget. This allows it to be embedded inside of a Google
 403 Spreadsheet. For a demonstration of this, see <a
 404   href="http://spreadsheets.google.com/ccc?key=0Anx1yCqeL8YUdDR1c3pPREhraGhkWmdhaURjOXRncXc&hl=en">this
 405   spreadsheet</a>.</p>
 406
 407 <a name="baseball"><h2>Charting Fractions</h2>
 408 <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>
 409
 410 <ul>
 411 <li>The average of <code>a1/b1</code> and <code>a2/b2</code> is
 412 <code>(a1+a2)/(b1+b2)</code>, not <code>(a1/b1 + a2/b2)/2</code>.
 413 <li>The normal approximation is not always applicable and more sophisticated
 414 confidence intervals (e.g. the <a
 415 href="http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval">Wilson
 416 confidence interval</a>) must be employed to avoid ratios that exceed 100% or
 417 go below 0%.
 418 </ul>
 419
 420 <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 421
 422 <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 423 <div id="baseballdiv" style="width:750px; height:300px;"></div>
 424 <script type="text/javascript">
 425 new Dygraph(document.getElementById("baseballdiv"),
 426             "suzuki-mariners.txt", {
 427               fractions: true,
 428               errorBars: true,
 429               showRoller: true,
 430               rollPeriod: 15
 431             });
 432 </script>
 433
 434 <p>Command:</p>
 435 <pre>
 436 new Dygraph(
 437   document.getElementById("baseballdiv"), "suzuki-mariners.txt",
 438   {
 439     fractions: true, errorBars: true,
 440     showRoller: true, rollPeriod: 15
 441   });
 442 </pre>
 443
 444 <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>
 445
 446 <p>A couple things to notice about this chart:</p>
 447 <ul>
 448 <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.
 449 <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.
 450 <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.
 451 <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.
 452 </ul>
 453
 454 <a name="stock"><h2>One last demo</h2>
 455
 456 <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>
 457
 458 <div id=dow_chart style="width:900px; height:350px;"></div>
 459 <script type="text/javascript">
 460   // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 461   dow = new Dygraph(
 462     document.getElementById('dow_chart'),
 463     "dow.txt",
 464     {
 465       showRoller: true,
 466       customBars: true,
 467       labelsKMB: true });
 468 </script>
 469 <!--
 470
 471 Here is a script to regenerate the Dow Jones plot:
 472
 473 # Get unadjusted DJIA data in a nice format:
 474 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 475 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
 476
 477 # Fetch and format the CPI data:
 478 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
 479 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-$2\t/g' > cpi-u.tsv
 480
 481 # Merge:
 482 join -t'       ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 483 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 484
 485 -->
 486
 487
 488 <a name="options">
 489 <h2>Other Options</h2>
 490 <p>These are the options that can be passed in through the optional third parameter of the Dygraph constructor. To see demonstrations of many of these options, browse the <a href="tests/">dygraphs tests</a> directory.</p>
 491
 492 <table class=thinborder width=900>
 493   <tr><th>Name</th><th>Sample Value</th><th>Description</th></tr>
 494   <tr>
 495     <td><b>includeZero</b></td>
 496     <td><code>true, false</code></td>
 497     <td>Usually, dygraphs will use the range of the data plus some padding to
 498     set the range of the y-axis. If this option is set, the y-axis will always
 499     include zero, typically as the lowest value. This can be used to avoid
 500     exaggerating the variance in the data.</td>
 501   </tr>
 502
 503   <tr>
 504     <td><b>rollPeriod</b></td>
 505     <td><code>7</code></td>
 506     <td>Number of days over which to average data. Discussed extensively above.</td>
 507   </tr>
 508
 509   <tr>
 510     <td><b>showRoller</b></td>
 511     <td><code>true</code></td>
 512     <td>Should the rolling average period text box be shown? Default is false.</td>
 513   </tr>
 514
 515   <tr>
 516     <td><b>colors</b></td>
 517     <td><code>['red',&nbsp;'#00FF00']</code></td>
 518     <td>List of colors for the data series. These can be of the form "#AABBCC"
 519       or "rgb(255,100,200)" or "yellow", etc. If not specified, equally-spaced
 520       points around a color wheel are used.</td>
 521   </tr>
 522
 523   <tr>
 524     <td><b>colorSaturation</b></td>
 525     <td><code>1.0</code></td>
 526     <td>If <b>colors</b> is not specified, saturation of the
 527       automatically-generated data series colors. (0.0-1.0, default:
 528       1.0)</td>
 529   </tr>
 530
 531   <tr>
 532     <td><b>colorValue</b></td>
 533     <td><code>0.5</code></td>
 534     <td>If colors is not specified, value of the data series colors, as in
 535       hue/saturation/value. (0.0-1.0, default 0.5)</td>
 536   </tr>
 537
 538   <tr>
 539     <td><b>clickCallback</b></td>
 540     <td><code>function(e,date){ alert(date); }</code></td>
 541     <td>A function to call when a data point is clicked. The function should take
 542       two arguments, the event object for the click and the date that was
 543       clicked. (default null)</td>
 544   </tr>
 545
 546   <tr>
 547     <td><b>zoomCallback</b></td>
 548     <td><code>function(minDate,maxDate) {}</code></td>
 549     <td>A function to call when the zoom window is changed (either by zooming
 550     in or out). minDate and maxDate are millis since epoch.</td>
 551   </tr>
 552
 553   <tr>
 554     <td><b>strokeWidth</b></td>
 555     <td><code>2.0</code></td>
 556     <td>Width of the data lines. This can be used to increase the contrast or
 557       some graphs. (default 1.0)</td>
 558   </tr>
 559
 560   <tr>
 561     <td><b>dateWindow</b></td>
 562     <td><code>[Date.parse('2006-01-01'),<br/>
 563         (new&nbsp;Date()).valueOf()]</code></td>
 564     <td>Initially zoom in on a section of the graph. Is of the form [earliest,
 565       latest], where earliest/latest are millis since epoch.  By default, the
 566       full range of the input is shown.</td>
 567   </tr>
 568
 569   <tr>
 570     <td><b>valueRange</b></td>
 571     <td><code>[10, 110]</code></td>
 572     <td>Explicitly set the vertical range of the graph to [low, high]. By
 573       default, some clever heuristics are used (see above).</td>
 574   </tr>
 575
 576   <tr>
 577     <td><b>labelsSeparateLines</b></td>
 578     <td><code>true</code></td>
 579     <td>Put &lt;br/&gt; between lines in the label string. Often used in
 580       conjunction with <b>labelsDiv</b>. (default false)</td>
 581   </tr>
 582
 583   <tr>
 584     <td><b>labelsDiv</b></td>
 585     <td><code>document.getElementById('foo')</code></td>
 586     <td>Show data labels in an external div, rather than on the graph. (default
 587       null)</td>
 588   </tr>
 589
 590   <tr>
 591     <td><b>labelsKMB</b></td>
 592     <td><code>true</code></td>
 593     <td>Show K/M/B for thousands/millions/billions on y-axis (default
 594       false).</td>
 595   </tr>
 596
 597   <tr>
 598     <td><b>labelsDivWidth</b></td>
 599     <td>250</td>
 600     <td>Width (in pixels) of the div which shows information on the
 601     currently-highlighted points.</td>
 602   </tr>
 603
 604   <tr>
 605     <td><b>labelsDivStyles</b></td>
 606     <td>{}</td>
 607     <td>Additional styles to apply to the currently-highlighted points div. For
 608     example, { 'font-weigth': 'bold' } will make the labels bold.</td>
 609   </tr>
 610
 611   <tr>
 612     <td><b>highlightCircleSize</b></td>
 613     <td><code>3</code></td>
 614     <td>Size (in pixels) of the dot drawn over highlighted points (default 3).</td>
 615   </tr>
 616
 617   <tr>
 618     <td><b>drawPoints</b></td>
 619     <td><code>false</code></td>
 620     <td>Draw a small dot at each point, in addition to a line going through
 621     the point. This makes the individual data points easier to see, but can
 622     increase visual clutter in the chart. Default: false</td>
 623   </tr>
 624
 625   <tr>
 626     <td><b>pointSize</b></td>
 627     <td><code>1.0</code></td>
 628     <td>The size of the dot to draw on each point in pixels (see
 629     drawPoints). A dot is always drawn when a point is "isolated", i.e.
 630     there is a missing point on either side of it. This also controls the
 631     size of those dots.</td>
 632   </tr>
 633
 634   <tr>
 635     <td><b>pixelsPerXLabel</b>, <b>pixelsPerYLabel</b></td>
 636     <td>50</td>
 637     <td>Number of pixels to require between each x- and y-label. Larger values
 638     will yield a sparser axis with fewer ticks. Defaults: 60 (x-axis), 30
 639     (y-axis).</td>
 640   </tr>
 641
 642   <tr>
 643     <td><b>xAxisLabelWidth</b>, <b>yAxisLabelWidth</b></td>
 644     <td>50</td>
 645     <td>Width (in pixels) of the x- and y-axis labels.</td>
 646   </tr>
 647
 648   <tr>
 649     <td><b>axisLabelFontSize</b></td>
 650     <td>14</td>
 651     <td>Size of the font (in pixels) to use in the axis labels, both x- and
 652     y-axis.</td>
 653   </tr>
 654
 655   <tr>
 656     <td><b>rightGap</b></td>
 657     <td>5</td>
 658     <td>Number of pixels to leave blank at the right edge of the Dygraph. This
 659     makes it easier to highlight the right-most data point.</td>
 660   </tr>
 661
 662   <tr>
 663     <td><b>errorBars</b></td>
 664     <td><code>false</code></td>
 665     <td>Does the data contain standard deviations? Setting this to true alters
 666       the input format (see above). (default false)</td>
 667   </tr>
 668
 669   <tr>
 670     <td><b>sigma</b></td>
 671     <td>2</td>
 672     <td>When errorBars is set, shade this many standard deviations above/below
 673     each point.</td>
 674   </tr>
 675
 676   <tr>
 677     <td><b>fractions</b></td>
 678     <td>false</td>
 679     <td>When set, attempt to parse each cell in the CSV file as "a/b", where a
 680     and b are integers. The ratio will be plotted. This allows computation of
 681     Wilson confidence intervals (see below).</td>
 682   </tr>
 683
 684   <tr>
 685     <td><b>wilsonInterval</b></td>
 686     <td>true</td>
 687     <td>Use in conjunction with the "fractions" option. Instead of plotting +/-
 688     N standard deviations, dygraphs will compute a Wilson confidence interval
 689     and plot that. This has more reasonable behavior for ratios close to 0 or
 690     1.</td>
 691   </tr>
 692
 693   <tr>
 694     <td><b>customBars</b></td>
 695     <td>false</td>
 696     <td>When set, parse each CSV cell as "low;middle;high". Error bars will be
 697     drawn for each point between low and high, with the series itself going
 698     through middle.</td>
 699   </tr>
 700 </table>
 701
 702 <h2>Common Gotchas</h2>
 703 <p>Here are a few problems that I've frequently run into while using the
 704 dygraphs library.</p>
 705
 706 <ul>
 707   <li>Make sure your CSV files are readable! If your graph isn't showing up,
 708   the XMLHttpRequest for the CSV file may be failing. You can determine whether
 709   this is the case using tools like <a
 710     href="http://www.getfirebug.com/">Firebug</a>.</li>
 711
 712   <li>Make sure your CSV files are in the correct format. They must be of the
 713   form <code>YYYYMMDD,series1,series2,...</code>. And if you set the
 714   <code>errorBars</code> property, make sure you alternate data series and
 715   standard deviations.</li>
 716
 717   <li>dygraphs are not happy when placed inside a <code>&lt;center&gt;</code>
 718   tag. This applies to the CSS <code>text-align</code> property as well. If you
 719   want to center a Dygraph, put it inside a table with "align=center"
 720   set.</li>
 721
 722   <li>Don't set the <code>dateWindow</code> property to a date. It expects
 723   milliseconds since epoch, which can be obtained from a JavaScript Date
 724   object's valueOf method.</li>
 725
 726   <li>Make sure you don't have any trailing commas in your call to the Dygraph
 727   constructor or in the options parameter. Firefox, Chrome and Safari ignore
 728   these but they can cause a graph to not display in Internet Explorer.</li>
 729 </ul>
 730
 731 <a name="policy">
 732 <h2>Data Policy</h2>
 733 <p>dygraphs is purely client-side JavaScript. It does not send your data to any
 734 servers -- the data is processed entirely in the client's browser.</p>
 735
 736 <p><font size=-1>Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></font></p>
 737
 738 </div>
 739
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