1 # Flot [![Build status](https://travis-ci.org/flot/flot.png)](https://travis-ci.org/flot/flot)

     2 

     3 ## About ##

     4 

     5 Flot is a Javascript plotting library for jQuery.  

     6 Read more at the website: <http://www.flotcharts.org/>

     7 

     8 Take a look at the the examples in examples/index.html; they should give a good

     9 impression of what Flot can do, and the source code of the examples is probably

    10 the fastest way to learn how to use Flot.

    11 

    12 

    13 ## Installation ##

    14 

    15 Just include the Javascript file after you've included jQuery.

    16 

    17 Generally, all browsers that support the HTML5 canvas tag are

    18 supported.

    19 

    20 For support for Internet Explorer < 9, you can use [Excanvas]

    21 [excanvas], a canvas emulator; this is used in the examples bundled

    22 with Flot. You just include the excanvas script like this:

    23 

    24 ```html

    25 <!--[if lte IE 8]><script language="javascript" type="text/javascript" src="excanvas.min.js"></script><![endif]-->

    26 ```

    27 

    28 If it's not working on your development IE 6.0, check that it has

    29 support for VML which Excanvas is relying on. It appears that some

    30 stripped down versions used for test environments on virtual machines

    31 lack the VML support.

    32 

    33 You can also try using [Flashcanvas][flashcanvas], which uses Flash to

    34 do the emulation. Although Flash can be a bit slower to load than VML,

    35 if you've got a lot of points, the Flash version can be much faster

    36 overall. Flot contains some wrapper code for activating Excanvas which

    37 Flashcanvas is compatible with.

    38 

    39 You need at least jQuery 1.2.6, but try at least 1.3.2 for interactive

    40 charts because of performance improvements in event handling.

    41 

    42 

    43 ## Basic usage ##

    44 

    45 Create a placeholder div to put the graph in:

    46 

    47 ```html

    48 <div id="placeholder"></div>

    49 ```

    50 

    51 You need to set the width and height of this div, otherwise the plot

    52 library doesn't know how to scale the graph. You can do it inline like

    53 this:

    54 

    55 ```html

    56 <div id="placeholder" style="width:600px;height:300px"></div>

    57 ```

    58 

    59 You can also do it with an external stylesheet. Make sure that the

    60 placeholder isn't within something with a display:none CSS property -

    61 in that case, Flot has trouble measuring label dimensions which

    62 results in garbled looks and might have trouble measuring the

    63 placeholder dimensions which is fatal (it'll throw an exception).

    64 

    65 Then when the div is ready in the DOM, which is usually on document

    66 ready, run the plot function:

    67 

    68 ```js

    69 $.plot($("#placeholder"), data, options);

    70 ```

    71 

    72 Here, data is an array of data series and options is an object with

    73 settings if you want to customize the plot. Take a look at the

    74 examples for some ideas of what to put in or look at the 

    75 [API reference](API.md). Here's a quick example that'll draw a line 

    76 from (0, 0) to (1, 1):

    77 

    78 ```js

    79 $.plot($("#placeholder"), [ [[0, 0], [1, 1]] ], { yaxis: { max: 1 } });

    80 ```

    81 

    82 The plot function immediately draws the chart and then returns a plot

    83 object with a couple of methods.

    84 

    85 

    86 ## What's with the name? ##

    87 

    88 First: it's pronounced with a short o, like "plot". Not like "flawed".

    89 

    90 So "Flot" rhymes with "plot".

    91 

    92 And if you look up "flot" in a Danish-to-English dictionary, some of

    93 the words that come up are "good-looking", "attractive", "stylish",

    94 "smart", "impressive", "extravagant". One of the main goals with Flot

    95 is pretty looks.

    96 

    97 

    98 ## Notes about the examples ##

    99 

   100 In order to have a useful, functional example of time-series plots using time

   101 zones, date.js from [timezone-js][timezone-js] (released under the Apache 2.0

   102 license) and the [Olson][olson] time zone database (released to the public

   103 domain) have been included in the examples directory.  They are used in

   104 examples/axes-time-zones/index.html.

   105 

   106 

   107 [excanvas]: http://code.google.com/p/explorercanvas/

   108 [flashcanvas]: http://code.google.com/p/flashcanvas/

   109 [timezone-js]: https://github.com/mde/timezone-js

   110 [olson]: http://ftp.iana.org/time-zones