I am creating a custom Tweet button with my own styles however it seems when you opt for customising your own you cannot use the data attributes (data-text, data-url etc.). The utilisation of the data attributes only seem available when you use the Twitter styled button that uses the widget javascript (http://platform.twitter.com/widgets.js).
Here is some code taken from the Twitter dev website. Below is the Tweet button using the data attributes:
<script src="http://platform.twitter.com/widgets.js" type="text/javascript"></script>
<div>
<a href="http://twitter.com/share" class="twitter-share-button"
data-url="http://dev.twitter.com/pages/tweet_button"
data-via="twitterapi"
data-text="Checking out this page about Tweet Buttons"
data-related="anywhere:The Javascript API"
data-count="vertical">Tweet</a>
</div>
Now below here is the 'Build your Own' Tweet button:
<style type="text/css" media="screen">
#custom-tweet-button a {
display: block;
padding: 2px 5px 2px 20px;
background: url('http://a4.twimg.com/images/favicon.gif') left center no-repeat;
border: 1px solid #ccc;
}
</style>
<div id="custom-tweet-button">
<a href="http://twitter.com/share?url=http%3A%2F%2Fdev.twitter.com%2Fpages%2Ftweet-button" target="_blank">Tweet</a>
</div>
Hopefully that all makes sense...
For some reason they won't let you use the Javascript data attributes with a custom button so you have to add them to the URL in your HTML. So for your example:
You would then add &text=your%20text
with your text.
<a href="http://twitter.com/share?url=http%3A%2F%2Fdev.twitter.com%2Fpages%2Ftweet-button&text=my%20text%20here" target="_blank">
The other codes are the same, just add &related=
etc.
Make sure you replace any spaces with %20
and that is it.