JavaScript HREF
You probably need a button, not a link.
Never use "javascript:" "#" or similar as the value of an href attribute.
The purpose of the href attribute is to specify a URL only. If you wish to run JavaScript on an element click, use a button instead.

Bad

<a href="javascript:;" id="share">Share on Facebook</a>
<script>
$('#share').on('click', function(e) {
// do fb share stuff
});
</script>

Good

<!-- a button created with JavaScript -->
<button id="share">Share on Facebook</button>
<script>
$('#share').on('click', function(e) {
// do fb share stuff
});
</script>

Even better

Use progressive enhancement:
<a href="http://www.facebook.com/share?id=12345" id="share">Share on Facebook</a>
<script>
$('#share').attr('role', 'button');
$('#share[role=button]').on('click', function(e) {
this.preventDefault();
// do fb share stuff
})
</script>
The screen reader will announce "Share on Facebook. Button" or fallback to "Share on Facebook. Link" if JavaScript is not ready or available.
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