 <p>in the javascript function. Then it will not postback.</p> <pre><code> $j(".colorBoxLink").click((function () { $j("div#popup").show(); var editor = new wysihtml5.Editor("wysihtml5_textarea", { // id of textarea element toolbar: "wysihtml5-toolbar", // id of toolbar element parserRules: wysihtml5ParserRules, // defined in parser rules set stylesheets: ["Styles/wysihtml5.css", "Styles/wysihtml5.css"] }); $j.colorbox({ inline: true, href: "#popup", modal: true, scrolling: false, onCleanup: function () { $j("div#popup").hide(); } }); return false; })); </code></pre>