How to find all TR with ID=pattern?

[rschaeferhig]

I need to find all the TR tags in a table where the ID for the TR starts with "CM". Not all the TR's have ID's. I can get the collection of TR tags using x=document.getelementsbytagname('tr'), but how to inspect the ID's of each tag in the collection?

Obviously a real newbie....

[Fang]

var aTR=document.getElementsByTagName('tr');
for(var i=0; i<aTR.length; i++) {
    if(aTR[i].id.match(/^(cm)/i)) {
    	alert(aTR[i].id);
        }
    }