Before you can track conversions or target audiences using a remarketing list, you need to create a UET tag in Microsoft Advertising and then add the UET tag tracking code to every page of your website. We strongly recommend that you use JavaScript to ensure accurate conversion tracking.
A JavaScript tracking code allows Microsoft Advertising to collect richer activity data that improves conversion tracking and remarketing in paid search. The only time you shouldn't use this is if your website has rules that prohibit JavaScript from being installed on it.
Here is an example of the JavaScript UET tag tracking code:
<script>
(function(w,d,t,r,u){var f,n,i;w[u]=w[u]||[]
,f=function(){var o={ti:"TAG_ID_HERE", enableAutoSpaTracking: true};
o.q=w[u],w[u]=new UET(o),w[u].push("pageLoad")}
,n=d.createElement(t),n.src=r,n.async=1,n.onload=n
.onreadystatechange=function()
{var s=this.readyState;s
&&s!=="loaded"&&
s!=="complete"||(f(),n.onload=n.
onreadystatechange=null)},i=
d.getElementsByTagName(t)[0],i.
parentNode.insertBefore(n,i)})(window,document,"script","
//bat.bing.com/bat.js","uetq");
</script>
Don't know what UET is? See What is UET and how can it help me?