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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="#stock">Stock chart</a>
  61   <li><a href="#options">Options Reference</a>
  62   <li><a href="#policy">Data Policy</a>
  63   </ul>
  64
  65 <li><b>Project</b>
  66   <ul>
  67   <li><a href="http://github.com/danvk/dygraphs">Source</a>
  68   <li><a href="http://code.google.com/p/dygraphs/issues/">Issues</a>
  69   <li><a href="http://code.google.com/p/dygraphs/issues/entry">Report Bug</a>
  70   <li><a href="mailto:danvdk [at] gmail">Contact</a>
  71   </ul>
  72
  73
  74 <li><b>Gallery</b>
  75   <ul>
  76   <li><a href="tests/demo.html">Basic Demo</a>
  77   <li><a href="tests/gviz.html">GViz Demo</a>
  78   <li><a href="tests/plotter.html">Equation Plotter</a>
  79   <li><a href="tests/perf.html">Performance Test</a>
  80   <li><a href="tests/perf.html">Fractions</a>
  81
  82   <li><a href="tests/label-div.html">Labels in a DIV</a>
  83   <li><a href="tests/numeric-axis.html">Numeric Axis</a>
  84   <li><a href="tests/draw-points.html">Dotted Points</a>
  85
  86   <li><a href="tests/native-format.html">Native Format</a>
  87   <li><a href="tests/grid_dot.html">Crazy Styles</a>
  88   <li><a href="tests/spacing.html">Tick spacing</a>
  89   <li><a href="tests/callback.html">Callbacks</a>
  90   <li><a href="tests/crosshair.html">Crosshairs</a>
  91   <li><a href="tests/hourly.html">Hourly/Minutely data</a>
  92
  93   <li><a href="tests/isolated-points.html">Isolated Points</a>
  94   <li><a href="tests/missing-data.html">Missing Data</a>
  95
  96   <li><a href="tests/border.html">Bordered chart</a>
  97   <li><a href="tests/custom-bars.html">Custom Bars</a>
  98   <li><a href="tests/customLabel.html">Custom Label Styles</a>
  99   <li><a href="tests/dygraph.html">Minimal Example</a>
 100   <li><a href="tests/negative.html">Negative Numbers</a>
 101   <li><a href="tests/noise.html">Noisy Data</a>
 102   <li><a href="tests/two-series.html">Multiple Series</a>
 103   </ul>
 104 </ul>
 105 </div>
 106
 107 <div id="content">
 108 <p><span style="font-size:28pt;">dygraphs JavaScript Visualization Library</span><br/>
 109 <a href="http://github.com/danvk/dygraphs">http://github.com/danvk/dygraphs</a><br/>
 110 See <a href="tests/">gallery</a> and <a href="http://code.google.com/p/dygraphs/issues/">open issues</a></p>
 111
 112 <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>
 113
 114 <h3>Features</h3>
 115 <ul>
 116   <li>Plots time series without using an external server or Flash</li>
 117   <li>Supports error bands around data series</li>
 118   <li>Displays values on mouseover (this makes it easily discoverable)</li>
 119   <li>Interactive zoom</li>
 120   <li>Adjustable averaging period</li>
 121   <li>Customizable click-through actions</li>
 122   <li>Compatible with the Google Visualization API</li>
 123   <li>Works in Internet Explorer (using excanvas)</li>
 124   <li>Intelligent defaults make it easy to use</li>
 125   <li>Lightweight (45kb) and responsive</li>
 126 </ul>
 127
 128 <a name="demo"><h2>Demo</h2>
 129 <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>
 130 <div id="title" style="width:800px; text-align:center; font-weight: bold; font-size: 125%;">Temperatures in New York vs. San Francisco</div>
 131 <div id="demodiv" style="width:800px; height:320px;"></div>
 132 <script type="text/javascript">
 133   g = new Dygraph(
 134           document.getElementById("demodiv"),
 135           "ny-vs-sf.txt",
 136           {
 137             rollPeriod: 14,
 138             showRoller: true,
 139             customBars: true,
 140             yAxisLabelWidth: 30
 141           }
 142       );
 143 </script>
 144
 145 <p>Some things to notice:</p>
 146 <ul>
 147 <li>There's less seasonal temperature variation in SF than in NY.
 148 <li>The difference is about 15&deg; F for SF vs. 50&deg; F for NY.
 149 <li>The daily data (set rolling period to 1) is quite noisy and hides this conclusion.
 150 <li>Using a 14-day moving average makes it clearer. A 100-day rolling period averages out nearly all the specifics from the data.
 151 <li>There's a gap in the data for SF, when the weather station was down (zoom into October 2007 to see it).
 152 <li>The bands around each point indicate average highs and lows.
 153 <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.
 154 </ul>
 155
 156 <p>For more demos, browse the dygraph <a href="tests/">tests</a> directory.</p>
 157
 158 <a name="usage"><h2>Usage</h2>
 159
 160 <p>To use dygraphs, include the <code>dygraph-combined.js</code> JavaScript file and instantiate a <code>Dygraph</code> object.</p>
 161
 162 <p>Here's a basic example to get things started:</p>
 163
 164 <table>
 165   <tr><th>HTML</th>
 166       <td rowspan=2><img src=arrow.gif /></td>
 167       <th>Output</th></tr>
 168 <tr>
 169 <td valign=top><pre>
 170 &lt;html&gt;
 171 &lt;head&gt;
 172 &lt;script type="text/javascript"
 173   src="dygraph-combined.js"&gt;&lt;/script&gt;
 174 &lt;/head&gt;
 175 &lt;body&gt;
 176 &lt;div id="graphdiv"&gt;&lt;/div&gt;
 177 &lt;script type="text/javascript"&gt;
 178   g = new Dygraph(
 179         // containing div
 180         document.getElementById("graphdiv"),
 181         // CSV or path to a CSV file.
 182         "Date,Temperature\n" +
 183         "2008-05-07,75\n" +
 184         "2008-05-08,70\n" +
 185         "2008-05-09,80\n"
 186       );
 187 &lt;/script&gt;
 188 &lt;/body&gt;
 189 &lt;/html&gt;
 190 </pre>
 191 </td><td valign=top>
 192   <div id="graphdiv"></div>
 193 </td></tr></table>
 194
 195 <script type="text/javascript">
 196   g1 = new Dygraph(
 197        document.getElementById("graphdiv"),  // containing div
 198        "Date,Temperature\n" +                // CSV or path to a CSV file.
 199        "2008-05-07,75\n" +
 200        "2008-05-08,70\n" +
 201        "2008-05-09,80\n"
 202      );
 203 </script>
 204
 205 <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>
 206
 207 <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>
 208
 209 <table>
 210   <tr><th>HTML</th>
 211       <td rowspan=2><img src=arrow.gif /></td>
 212       <th>Output</th></tr>
 213 <tr>
 214 <td valign=top><pre>
 215 &lt;html&gt;
 216 &lt;head&gt;
 217 &lt;script type="text/javascript"
 218   src="dygraph-combined.js"&gt;&lt;/script&gt;
 219 &lt;/head&gt;
 220 &lt;body&gt;
 221 &lt;div id="graphdiv"
 222   style="width:500px; height:300px;"&gt;&lt;/div&gt;
 223 &lt;script type="text/javascript"&gt;
 224   new Dygraph(
 225     document.getElementById("graphdiv"),
 226     "temperatures.csv",  // path to CSV file
 227     {}                   // options
 228   );
 229 &lt;/script&gt;
 230 &lt;/body&gt;
 231 &lt;/html&gt;
 232 </pre>
 233 </td><td valign=top>
 234   <div id="graphdiv2" style="width:500px; height:300px;"></div>
 235 </td></tr></table>
 236
 237 <script type="text/javascript">
 238   g2 = new Dygraph(
 239         document.getElementById("graphdiv2"),
 240         "temperatures.csv", {}
 241       );
 242 </script>
 243
 244 <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>
 245
 246 <ul>
 247   <li>The Dygraph sent off an XHR to get the temperatures.csv file.</li>
 248   <li>The labels were taken from the first line of <code>temperatures.csv</code>, which is <code>Date,High,Low</code>.</li>
 249   <li>The Dygraph automatically chose two different, easily-distinguishable colors for the two data series.</li>
 250   <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>
 251   <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>
 252   <li>The data is very spiky. A moving average would be easier to interpret.</li>
 253 </ul>
 254
 255 <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>
 256
 257 <table>
 258   <tr><th>HTML</th>
 259       <td rowspan=2><img src=arrow.gif /></td>
 260       <th>Output</th></tr>
 261 <tr>
 262 <td valign=top><pre>
 263 &lt;html&gt;
 264 &lt;head&gt;
 265 &lt;script type="text/javascript"
 266   src="dygraph-combined.js"&gt;&lt;/script&gt;
 267 &lt;/head&gt;
 268 &lt;body&gt;
 269 &lt;div id="graphdiv"
 270   style="width:500px; height:300px;"&gt;&lt;/div&gt;
 271 &lt;script type="text/javascript"&gt;
 272   g = new Dygraph(
 273         document.getElementById("graphdiv"),
 274         "temperatures.csv",
 275         { rollPeriod: 7,
 276           showRoller: true,
 277         }
 278       );
 279 &lt;/script&gt;
 280 &lt;/body&gt;
 281 &lt;/html&gt;
 282 </pre>
 283 </td><td valign=top>
 284   <div id="graphdiv3" style="width:500px; height:300px;"></div>
 285 </td></tr></table>
 286
 287 <script type="text/javascript">
 288   g3 = new Dygraph(
 289         document.getElementById("graphdiv3"),
 290         "temperatures.csv",
 291         { rollPeriod: 7,
 292           showRoller: true });
 293 </script>
 294
 295 <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>
 296
 297 <h2>Error Bars</h2>
 298 <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>
 299
 300 <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>
 301
 302 <table>
 303   <tr><th>HTML</th>
 304       <td rowspan=2><img src=arrow.gif /></td>
 305       <th>Output</th></tr>
 306 <tr>
 307 <td valign=top><pre>
 308 &lt;html&gt;
 309 &lt;head&gt;
 310 &lt;script type="text/javascript"
 311   src="combined.js"&gt;&lt;/script&gt;
 312 &lt;/head&gt;
 313 &lt;body&gt;
 314 &lt;div id="graphdiv"
 315  style="width:600px; height:300px;"
 316  &gt;&lt;/div&gt;
 317 &lt;script type="text/javascript"&gt;
 318 $ = document.getElementById;
 319 g = new Dygraph(
 320   $("graphdiv"),
 321   "twonormals.csv",
 322   { rollPeriod: 7,
 323     showRoller: true,
 324     errorBars: true,
 325     valueRange: [50,125]
 326   }
 327 );
 328 &lt;/script&gt;
 329 &lt;/body&gt;
 330 &lt;/html&gt;
 331 </pre>
 332 </td><td valign=top>
 333   <div id="graphdiv4" style="width:600px; height:300px;"></div>
 334 </td></tr></table>
 335
 336 <script type="text/javascript">
 337 $ = document.getElementById;
 338 new Dygraph(
 339   document.getElementById("graphdiv4"),
 340   "twonormals.csv",
 341   { rollPeriod: 14,
 342     showRoller: true,
 343     errorBars: true,
 344     valueRange: [50, 125]
 345   }
 346 );
 347 </script>
 348
 349 <p>Things to note here:</p>
 350 <ul>
 351   <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>
 352   <li>The first line of the CSV file doesn't mention the error columns. In this case, it's just "Date,Series1,Series2".</li>
 353   <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>
 354   <li>The error bars are partially transparent. This can be seen when they overlap one another.</li>
 355 </ul>
 356
 357 <a name="ie"><h2>Internet Explorer Compatibility</h2>
 358
 359 <p>The dygraphs library relies heavily on HTML's &lt;canvas&gt; tag, which
 360 Microsoft Internet Explorer does not support. Fortunately, some clever engineers
 361 created the <a href="http://code.google.com/p/explorercanvas/">excanvas</a>
 362 library, which imlements the &lt;canvas&gt; tag in IE using VML.</p>
 363
 364 <p>You can add IE support to any page using dygraphs by including the following
 365 in your page:</p>
 366
 367 <pre>
 368 &lt;head&gt;
 369 &lt;!--[if IE]&gt;&lt;script src="excanvas.js"&gt;&lt;/script&gt;&lt;![endif]--&gt;
 370 &lt;/head&gt;
 371 </pre>
 372
 373 <p>This works quite well in practice. Charts are responsive, even under VML
 374 emulation.</p>
 375
 376 <p>One common gotcha to look out for: make sure you don't have any trailing
 377 commas in parameter lists, e.g.</p>
 378
 379 <pre>new Dygraph(el, data, {
 380   showRoller:true,  // &lt;-- note trailing comma
 381 })</pre>
 382
 383 <p>Most browsers will ignore the trailing comma, but it will break under IE.</p>
 384
 385 <a name="stock"><h2>One last demo</h2>
 386
 387 <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>
 388
 389 <div id=dow_chart style="width:900px; height:350px;"></div>
 390 <script type="text/javascript">
 391   // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 392   dow = new Dygraph(
 393     document.getElementById('dow_chart'),
 394     "dow.txt",
 395     {
 396       showRoller: true,
 397       customBars: true,
 398       labelsKMB: true });
 399 </script>
 400 <!--
 401
 402 Here is a script to regenerate the Dow Jones plot:
 403
 404 # Get unadjusted DJIA data in a nice format:
 405 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 406 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
 407
 408 # Fetch and format the CPI data:
 409 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
 410 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-$2\t/g' > cpi-u.tsv
 411
 412 # Merge:
 413 join -t'       ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 414 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 415
 416 -->
 417
 418
 419 <a name="options">
 420 <h2>Other Options</h2>
 421 <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>
 422
 423 <table class=thinborder width=900>
 424   <tr><th>Name</th><th>Sample Value</th><th>Description</th></tr>
 425   <tr>
 426     <td><b>includeZero</b></td>
 427     <td><code>true, false</code></td>
 428     <td>Usually, dygraphs will use the range of the data plus some padding to
 429     set the range of the y-axis. If this option is set, the y-axis will always
 430     include zero, typically as the lowest value. This can be used to avoid
 431     exaggerating the variance in the data.</td>
 432   </tr>
 433
 434   <tr>
 435     <td><b>rollPeriod</b></td>
 436     <td><code>7</code></td>
 437     <td>Number of days over which to average data. Discussed extensively above.</td>
 438   </tr>
 439
 440   <tr>
 441     <td><b>showRoller</b></td>
 442     <td><code>true</code></td>
 443     <td>Should the rolling average period text box be shown? Default is false.</td>
 444   </tr>
 445
 446   <tr>
 447     <td><b>colors</b></td>
 448     <td><code>['red',&nbsp;'#00FF00']</code></td>
 449     <td>List of colors for the data series. These can be of the form "#AABBCC"
 450       or "rgb(255,100,200)" or "yellow", etc. If not specified, equally-spaced
 451       points around a color wheel are used.</td>
 452   </tr>
 453
 454   <tr>
 455     <td><b>colorSaturation</b></td>
 456     <td><code>1.0</code></td>
 457     <td>If <b>colors</b> is not specified, saturation of the
 458       automatically-generated data series colors. (0.0-1.0, default:
 459       1.0)</td>
 460   </tr>
 461
 462   <tr>
 463     <td><b>colorValue</b></td>
 464     <td><code>0.5</code></td>
 465     <td>If colors is not specified, value of the data series colors, as in
 466       hue/saturation/value. (0.0-1.0, default 0.5)</td>
 467   </tr>
 468
 469   <tr>
 470     <td><b>clickCallback</b></td>
 471     <td><code>function(e,date){ alert(date); }</code></td>
 472     <td>A function to call when a data point is clicked. The function should take
 473       two arguments, the event object for the click and the date that was
 474       clicked. (default null)</td>
 475   </tr>
 476
 477   <tr>
 478     <td><b>zoomCallback</b></td>
 479     <td><code>function(minDate,maxDate) {}</code></td>
 480     <td>A function to call when the zoom window is changed (either by zooming
 481     in or out). minDate and maxDate are millis since epoch.</td>
 482   </tr>
 483
 484   <tr>
 485     <td><b>strokeWidth</b></td>
 486     <td><code>2.0</code></td>
 487     <td>Width of the data lines. This can be used to increase the contrast or
 488       some graphs. (default 1.0)</td>
 489   </tr>
 490
 491   <tr>
 492     <td><b>dateWindow</b></td>
 493     <td><code>[Date.parse('2006-01-01'),<br/>
 494         (new&nbsp;Date()).valueOf()]</code></td>
 495     <td>Initially zoom in on a section of the graph. Is of the form [earliest,
 496       latest], where earliest/latest are millis since epoch.  By default, the
 497       full range of the input is shown.</td>
 498   </tr>
 499
 500   <tr>
 501     <td><b>valueRange</b></td>
 502     <td><code>[10, 110]</code></td>
 503     <td>Explicitly set the vertical range of the graph to [low, high]. By
 504       default, some clever heuristics are used (see above).</td>
 505   </tr>
 506
 507   <tr>
 508     <td><b>labelsSeparateLines</b></td>
 509     <td><code>true</code></td>
 510     <td>Put &lt;br/&gt; between lines in the label string. Often used in
 511       conjunction with <b>labelsDiv</b>. (default false)</td>
 512   </tr>
 513
 514   <tr>
 515     <td><b>labelsDiv</b></td>
 516     <td><code>document.getElementById('foo')</code></td>
 517     <td>Show data labels in an external div, rather than on the graph. (default
 518       null)</td>
 519   </tr>
 520
 521   <tr>
 522     <td><b>labelsKMB</b></td>
 523     <td><code>true</code></td>
 524     <td>Show K/M/B for thousands/millions/billions on y-axis (default
 525       false).</td>
 526   </tr>
 527
 528   <tr>
 529     <td><b>labelsDivWidth</b></td>
 530     <td>250</td>
 531     <td>Width (in pixels) of the div which shows information on the
 532     currently-highlighted points.</td>
 533   </tr>
 534
 535   <tr>
 536     <td><b>labelsDivStyles</b></td>
 537     <td>{}</td>
 538     <td>Additional styles to apply to the currently-highlighted points div. For
 539     example, { 'font-weigth': 'bold' } will make the labels bold.</td>
 540   </tr>
 541
 542   <tr>
 543     <td><b>highlightCircleSize</b></td>
 544     <td><code>3</code></td>
 545     <td>Size (in pixels) of the dot drawn over highlighted points (default 3).</td>
 546   </tr>
 547
 548   <tr>
 549     <td><b>drawPoints</b></td>
 550     <td><code>false</code></td>
 551     <td>Draw a small dot at each point, in addition to a line going through
 552     the point. This makes the individual data points easier to see, but can
 553     increase visual clutter in the chart. Default: false</td>
 554   </tr>
 555
 556   <tr>
 557     <td><b>pointSize</b></td>
 558     <td><code>1.0</code></td>
 559     <td>The size of the dot to draw on each point in pixels (see
 560     drawPoints). A dot is always drawn when a point is "isolated", i.e.
 561     there is a missing point on either side of it. This also controls the
 562     size of those dots.</td>
 563   </tr>
 564
 565   <tr>
 566     <td><b>pixelsPerXLabel</b>, <b>pixelsPerYLabel</b></td>
 567     <td>50</td>
 568     <td>Number of pixels to require between each x- and y-label. Larger values
 569     will yield a sparser axis with fewer ticks. Defaults: 60 (x-axis), 30
 570     (y-axis).</td>
 571   </tr>
 572
 573   <tr>
 574     <td><b>xAxisLabelWidth</b>, <b>yAxisLabelWidth</b></td>
 575     <td>50</td>
 576     <td>Width (in pixels) of the x- and y-axis labels.</td>
 577   </tr>
 578
 579   <tr>
 580     <td><b>axisLabelFontSize</b></td>
 581     <td>14</td>
 582     <td>Size of the font (in pixels) to use in the axis labels, both x- and
 583     y-axis.</td>
 584   </tr>
 585
 586   <tr>
 587     <td><b>rightGap</b></td>
 588     <td>5</td>
 589     <td>Number of pixels to leave blank at the right edge of the Dygraph. This
 590     makes it easier to highlight the right-most data point.</td>
 591   </tr>
 592
 593   <tr>
 594     <td><b>errorBars</b></td>
 595     <td><code>false</code></td>
 596     <td>Does the data contain standard deviations? Setting this to true alters
 597       the input format (see above). (default false)</td>
 598   </tr>
 599
 600   <tr>
 601     <td><b>sigma</b></td>
 602     <td>2</td>
 603     <td>When errorBars is set, shade this many standard deviations above/below
 604     each point.</td>
 605   </tr>
 606
 607   <tr>
 608     <td><b>fractions</b></td>
 609     <td>false</td>
 610     <td>When set, attempt to parse each cell in the CSV file as "a/b", where a
 611     and b are integers. The ratio will be plotted. This allows computation of
 612     Wilson confidence intervals (see below).</td>
 613   </tr>
 614
 615   <tr>
 616     <td><b>wilsonInterval</b></td>
 617     <td>true</td>
 618     <td>Use in conjunction with the "fractions" option. Instead of plotting +/-
 619     N standard deviations, dygraphs will compute a Wilson confidence interval
 620     and plot that. This has more reasonable behavior for ratios close to 0 or
 621     1.</td>
 622   </tr>
 623
 624   <tr>
 625     <td><b>customBars</b></td>
 626     <td>false</td>
 627     <td>When set, parse each CSV cell as "low;middle;high". Error bars will be
 628     drawn for each point between low and high, with the series itself going
 629     through middle.</td>
 630   </tr>
 631 </table>
 632
 633 <h2>Common Gotchas</h2>
 634 <p>Here are a few problems that I've frequently run into while using the
 635 dygraphs library.</p>
 636
 637 <ul>
 638   <li>Make sure your CSV files are readable! If your graph isn't showing up,
 639   the XMLHttpRequest for the CSV file may be failing. You can determine whether
 640   this is the case using tools like <a
 641     href="http://www.getfirebug.com/">Firebug</a>.</li>
 642
 643   <li>Make sure your CSV files are in the correct format. They must be of the
 644   form <code>YYYYMMDD,series1,series2,...</code>. And if you set the
 645   <code>errorBars</code> property, make sure you alternate data series and
 646   standard deviations.</li>
 647
 648   <li>dygraphs are not happy when placed inside a <code>&lt;center&gt;</code>
 649   tag. This applies to the CSS <code>text-align</code> property as well. If you
 650   want to center a Dygraph, put it inside a table with "align=center"
 651   set.</li>
 652
 653   <li>Don't set the <code>dateWindow</code> property to a date. It expects
 654   milliseconds since epoch, which can be obtained from a JavaScript Date
 655   object's valueOf method.</li>
 656
 657   <li>Make sure you don't have any trailing commas in your call to the Dygraph
 658   constructor or in the options parameter. Firefox, Chrome and Safari ignore
 659   these but they can cause a graph to not display in Internet Explorer.</li>
 660 </ul>
 661
 662 <a name="policy">
 663 <h2>Data Policy</h2>
 664 <p>dygraphs is purely client-side JavaScript. It does not send your data to any
 665 servers -- the data is processed entirely in the client's browser.</p>
 666
 667 <p><font size=-1>Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></font></p>
 668
 669 </div>
 670
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