Google Tag Manager与JS的代码集成

Question

我想将GTM代码与JS集成，但是我遇到了一些错误。我错了什么？

var domain = window.location.hostname;
if(domain == 'domain a' || domain == 'domain b'){
    gtm = '456123';
}else{
    gtm = '798123';
}
var gtmCode = '<noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-'+gtm+'" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript><script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({\'gtm.start\':new Date().getTime(),event:\'gtm.js\'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!=\'dataLayer\'?\'&l=\'+l:\'\';j.async=true;j.src=\'//www.googletagmanager.com/gtm.js?id=\'+i+dl;f.parentNode.insertBefore(j,f);})(window,document,\'script\',\'dataLayer\',\'GTM-'+gtm+'\');</script>';
alert(gtmCode);

感谢您的帮助！

干杯，马可