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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="#baseball">Baseball chart</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="baseball"><h2>Charting Fractions</h2>
 358 <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>
 359
 360 <ul>
 361 <li>The average of <code>a1/b1</code> and <code>a2/b2</code> is
 362 <code>(a1+a2)/(b1+b2)</code>, not <code>(a1/b1 + a2/b2)/2</code>.
 363 <li>The normal approximation is not always applicable and more sophisticated
 364 confidence intervals (e.g. the <a
 365 href="http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval">Wilson
 366 confidence interval</a>) must be employed to avoid ratios that exceed 100% or
 367 go below 0%.
 368 </ul>
 369
 370 <p>Fortunately, dygraphs handles both of these for you! Here's a chart and the command that generated it:</p>
 371
 372 <div style="width:750px; text-align:center; font-weight: bold; font-size: 125%;">Batting Average for Ichiro Suzuki vs. Mariners (2004)</div>
 373 <div id="baseballdiv" style="width:750px; height:300px;"></div>
 374 <script type="text/javascript">
 375 new Dygraph(document.getElementById("baseballdiv"),
 376             "suzuki-mariners.txt", {
 377               fractions: true,
 378               errorBars: true,
 379               showRoller: true,
 380               rollPeriod: 15
 381             });
 382 </script>
 383
 384 <p>Command:</p>
 385 <pre>
 386 new Dygraph(
 387   document.getElementById("baseballdiv"), "suzuki-mariners.txt",
 388   {
 389     fractions: true, errorBars: true,
 390     showRoller: true, rollPeriod: 15
 391   });
 392 </pre>
 393
 394 <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>
 395
 396 <p>A couple things to notice about this chart:</p>
 397 <ul>
 398 <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.
 399 <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.
 400 <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.
 401 <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.
 402 </ul>
 403
 404 <a name="stock"><h2>One last demo</h2>
 405
 406 <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>
 407
 408 <div id=dow_chart style="width:900px; height:350px;"></div>
 409 <script type="text/javascript">
 410   // From http://www.econstats.com/eqty/eq_d_mi_3.csv
 411   dow = new Dygraph(
 412     document.getElementById('dow_chart'),
 413     "dow.txt",
 414     {
 415       showRoller: true,
 416       customBars: true,
 417       labelsKMB: true });
 418 </script>
 419 <!--
 420
 421 Here is a script to regenerate the Dow Jones plot:
 422
 423 # Get unadjusted DJIA data in a nice format:
 424 curl -O http://www.econstats.com/eqty/eq_d_mi_3.csv
 425 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
 426
 427 # Fetch and format the CPI data:
 428 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
 429 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-$2\t/g' > cpi-u.tsv
 430
 431 # Merge:
 432 join -t'       ' cpi-u.tsv monthly-djia.tsv > annotated-djia.tsv
 433 perl -ne 'BEGIN{print "Month,Nominal,Real\n"} chomp; ($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
 434
 435 -->
 436
 437
 438 <a name="options">
 439 <h2>Other Options</h2>
 440 <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>
 441
 442 <table class=thinborder width=900>
 443   <tr><th>Name</th><th>Sample Value</th><th>Description</th></tr>
 444   <tr>
 445     <td><b>includeZero</b></td>
 446     <td><code>true, false</code></td>
 447     <td>Usually, dygraphs will use the range of the data plus some padding to
 448     set the range of the y-axis. If this option is set, the y-axis will always
 449     include zero, typically as the lowest value. This can be used to avoid
 450     exaggerating the variance in the data.</td>
 451   </tr>
 452
 453   <tr>
 454     <td><b>rollPeriod</b></td>
 455     <td><code>7</code></td>
 456     <td>Number of days over which to average data. Discussed extensively above.</td>
 457   </tr>
 458
 459   <tr>
 460     <td><b>showRoller</b></td>
 461     <td><code>true</code></td>
 462     <td>Should the rolling average period text box be shown? Default is false.</td>
 463   </tr>
 464
 465   <tr>
 466     <td><b>colors</b></td>
 467     <td><code>['red',&nbsp;'#00FF00']</code></td>
 468     <td>List of colors for the data series. These can be of the form "#AABBCC"
 469       or "rgb(255,100,200)" or "yellow", etc. If not specified, equally-spaced
 470       points around a color wheel are used.</td>
 471   </tr>
 472
 473   <tr>
 474     <td><b>colorSaturation</b></td>
 475     <td><code>1.0</code></td>
 476     <td>If <b>colors</b> is not specified, saturation of the
 477       automatically-generated data series colors. (0.0-1.0, default:
 478       1.0)</td>
 479   </tr>
 480
 481   <tr>
 482     <td><b>colorValue</b></td>
 483     <td><code>0.5</code></td>
 484     <td>If colors is not specified, value of the data series colors, as in
 485       hue/saturation/value. (0.0-1.0, default 0.5)</td>
 486   </tr>
 487
 488   <tr>
 489     <td><b>clickCallback</b></td>
 490     <td><code>function(e,date){ alert(date); }</code></td>
 491     <td>A function to call when a data point is clicked. The function should take
 492       two arguments, the event object for the click and the date that was
 493       clicked. (default null)</td>
 494   </tr>
 495
 496   <tr>
 497     <td><b>zoomCallback</b></td>
 498     <td><code>function(minDate,maxDate) {}</code></td>
 499     <td>A function to call when the zoom window is changed (either by zooming
 500     in or out). minDate and maxDate are millis since epoch.</td>
 501   </tr>
 502
 503   <tr>
 504     <td><b>strokeWidth</b></td>
 505     <td><code>2.0</code></td>
 506     <td>Width of the data lines. This can be used to increase the contrast or
 507       some graphs. (default 1.0)</td>
 508   </tr>
 509
 510   <tr>
 511     <td><b>dateWindow</b></td>
 512     <td><code>[Date.parse('2006-01-01'),<br/>
 513         (new&nbsp;Date()).valueOf()]</code></td>
 514     <td>Initially zoom in on a section of the graph. Is of the form [earliest,
 515       latest], where earliest/latest are millis since epoch.  By default, the
 516       full range of the input is shown.</td>
 517   </tr>
 518
 519   <tr>
 520     <td><b>valueRange</b></td>
 521     <td><code>[10, 110]</code></td>
 522     <td>Explicitly set the vertical range of the graph to [low, high]. By
 523       default, some clever heuristics are used (see above).</td>
 524   </tr>
 525
 526   <tr>
 527     <td><b>labelsSeparateLines</b></td>
 528     <td><code>true</code></td>
 529     <td>Put &lt;br/&gt; between lines in the label string. Often used in
 530       conjunction with <b>labelsDiv</b>. (default false)</td>
 531   </tr>
 532
 533   <tr>
 534     <td><b>labelsDiv</b></td>
 535     <td><code>document.getElementById('foo')</code></td>
 536     <td>Show data labels in an external div, rather than on the graph. (default
 537       null)</td>
 538   </tr>
 539
 540   <tr>
 541     <td><b>labelsKMB</b></td>
 542     <td><code>true</code></td>
 543     <td>Show K/M/B for thousands/millions/billions on y-axis (default
 544       false).</td>
 545   </tr>
 546
 547   <tr>
 548     <td><b>labelsDivWidth</b></td>
 549     <td>250</td>
 550     <td>Width (in pixels) of the div which shows information on the
 551     currently-highlighted points.</td>
 552   </tr>
 553
 554   <tr>
 555     <td><b>labelsDivStyles</b></td>
 556     <td>{}</td>
 557     <td>Additional styles to apply to the currently-highlighted points div. For
 558     example, { 'font-weigth': 'bold' } will make the labels bold.</td>
 559   </tr>
 560
 561   <tr>
 562     <td><b>highlightCircleSize</b></td>
 563     <td><code>3</code></td>
 564     <td>Size (in pixels) of the dot drawn over highlighted points (default 3).</td>
 565   </tr>
 566
 567   <tr>
 568     <td><b>drawPoints</b></td>
 569     <td><code>false</code></td>
 570     <td>Draw a small dot at each point, in addition to a line going through
 571     the point. This makes the individual data points easier to see, but can
 572     increase visual clutter in the chart. Default: false</td>
 573   </tr>
 574
 575   <tr>
 576     <td><b>pointSize</b></td>
 577     <td><code>1.0</code></td>
 578     <td>The size of the dot to draw on each point in pixels (see
 579     drawPoints). A dot is always drawn when a point is "isolated", i.e.
 580     there is a missing point on either side of it. This also controls the
 581     size of those dots.</td>
 582   </tr>
 583
 584   <tr>
 585     <td><b>pixelsPerXLabel</b>, <b>pixelsPerYLabel</b></td>
 586     <td>50</td>
 587     <td>Number of pixels to require between each x- and y-label. Larger values
 588     will yield a sparser axis with fewer ticks. Defaults: 60 (x-axis), 30
 589     (y-axis).</td>
 590   </tr>
 591
 592   <tr>
 593     <td><b>xAxisLabelWidth</b>, <b>yAxisLabelWidth</b></td>
 594     <td>50</td>
 595     <td>Width (in pixels) of the x- and y-axis labels.</td>
 596   </tr>
 597
 598   <tr>
 599     <td><b>axisLabelFontSize</b></td>
 600     <td>14</td>
 601     <td>Size of the font (in pixels) to use in the axis labels, both x- and
 602     y-axis.</td>
 603   </tr>
 604
 605   <tr>
 606     <td><b>rightGap</b></td>
 607     <td>5</td>
 608     <td>Number of pixels to leave blank at the right edge of the Dygraph. This
 609     makes it easier to highlight the right-most data point.</td>
 610   </tr>
 611
 612   <tr>
 613     <td><b>errorBars</b></td>
 614     <td><code>false</code></td>
 615     <td>Does the data contain standard deviations? Setting this to true alters
 616       the input format (see above). (default false)</td>
 617   </tr>
 618
 619   <tr>
 620     <td><b>sigma</b></td>
 621     <td>2</td>
 622     <td>When errorBars is set, shade this many standard deviations above/below
 623     each point.</td>
 624   </tr>
 625
 626   <tr>
 627     <td><b>fractions</b></td>
 628     <td>false</td>
 629     <td>When set, attempt to parse each cell in the CSV file as "a/b", where a
 630     and b are integers. The ratio will be plotted. This allows computation of
 631     Wilson confidence intervals (see below).</td>
 632   </tr>
 633
 634   <tr>
 635     <td><b>wilsonInterval</b></td>
 636     <td>true</td>
 637     <td>Use in conjunction with the "fractions" option. Instead of plotting +/-
 638     N standard deviations, dygraphs will compute a Wilson confidence interval
 639     and plot that. This has more reasonable behavior for ratios close to 0 or
 640     1.</td>
 641   </tr>
 642
 643   <tr>
 644     <td><b>customBars</b></td>
 645     <td>false</td>
 646     <td>When set, parse each CSV cell as "low;middle;high". Error bars will be
 647     drawn for each point between low and high, with the series itself going
 648     through middle.</td>
 649   </tr>
 650 </table>
 651
 652 <h2>Common Gotchas</h2>
 653 <p>Here are a few problems that I've frequently run into while using the
 654 dygraphs library.</p>
 655
 656 <ul>
 657   <li>Make sure your CSV files are readable! If your graph isn't showing up,
 658   the XMLHttpRequest for the CSV file may be failing. You can determine whether
 659   this is the case using tools like <a
 660     href="http://www.getfirebug.com/">Firebug</a>.</li>
 661
 662   <li>Make sure your CSV files are in the correct format. They must be of the
 663   form <code>YYYYMMDD,series1,series2,...</code>. And if you set the
 664   <code>errorBars</code> property, make sure you alternate data series and
 665   standard deviations.</li>
 666
 667   <li>dygraphs are not happy when placed inside a <code>&lt;center&gt;</code>
 668   tag. This applies to the CSS <code>text-align</code> property as well. If you
 669   want to center a Dygraph, put it inside a table with "align=center"
 670   set.</li>
 671
 672   <li>Don't set the <code>dateWindow</code> property to a date. It expects
 673   milliseconds since epoch, which can be obtained from a JavaScript Date
 674   object's valueOf method.</li>
 675
 676   <li>Make sure you don't have any trailing commas in your call to the Dygraph
 677   constructor or in the options parameter. Firefox, Chrome and Safari ignore
 678   these but they can cause a graph to not display in Internet Explorer.</li>
 679 </ul>
 680
 681 <a name="policy">
 682 <h2>Data Policy</h2>
 683 <p>dygraphs is purely client-side JavaScript. It does not send your data to any
 684 servers -- the data is processed entirely in the client's browser.</p>
 685
 686 <p><font size=-1>Created May 9, 2008 by <a href=mailto:danvdk@gmail.com>Dan Vanderkam</a></font></p>
 687
 688 </div>
 689
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