var thisBrowser = chkBrowse();

function chkBrowse() {
var agent=navigator.userAgent.toLowerCase();
if (agent.indexOf("safari") != -1) document.write("<link rel='stylesheet' href='/common/css/ir-alt.css' type='text/css'>");
if (agent.indexOf("opera") != -1) document.write("<link rel='stylesheet' href='/common/css/ir-alt.css' type='text/css'>");
}