jsSocials - UTM source
HTML
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.css">
<link rel="stylesheet" href="https://cdn.rawgit.com/tabalinas/jssocials/v0.2.0/dist/jssocials.css">
<script src="https://cdn.rawgit.com/tabalinas/jssocials/v0.2.0/dist/jssocials.min.js"></script>
<link rel="stylesheet" href="https://cdn.rawgit.com/tabalinas/jssocials/v0.2.0/dist/jssocials-theme-flat.css">
<div id="socials"></div>
JavaScript
var url = "http://google.com";
var text = "Some text to share";
jsSocials.shares.twitter.shareUrl = "https://twitter.com/share?url={url}%3Futm_source%3Dtwitter&text={text}&via={via}&hashtags={hashtags}";
$("#socials").jsSocials({
shares: [ "twitter", 'facebook']
})