Script doesn't executed

bellow script set in the IFRAME,
it doesn’t work with IE,
but, on the CHROME, FIREFOX, OPERA , work fine.

any idea???

thanks…

window.piwikAsyncInit = function () {
        try {
        	
            var ccTracker = Piwik.getTracker("//xxx.xx.xx.xx/piwik.php", 4);
	    ccTracker.setCookieDomain("*.xxx.xx");
	    ccTracker.setDomains("*.xxx.xx");     
       	    ccTracker.trackPageView();
	    ccTracker.enableLinkTracking();		
        } catch( err ) {}
    };
    
    (function() {
    	var c="//xxx.xx.xx.xx/";
    	var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
    	g.type='text/javascript'; g.async=true; g.defer=true; g.src=c+'piwik.js'; s.parentNode.insertBefore(g,s);
    })();