Sorry to say - your question is a little bit unclear. How do you want to change font color of an anchor tag?
You can do it easily using CSS like:
1. <a href="#">Change My Color</a>
<style type="text/css">
a{ color: #00ff00; }
</style>
2. <a class="myColor" href="#">Change My Color</a>
<style type="text/css">
.myColor{ color: #00ff00; }
</style>
OR
<style type="text/css">
a.myColor{ color: #00ff00; }
</style>
3. You can change its color using jQuery as well.
$(".myColor").css("color", "yellow");
Using CSS is better approach but Choice is yours !!
