Probably the quickest way you're gonna be able to do this...

gistfile1.txt

var divs = document.querySelectorAll ? document.querySelectorAll('div[id^=csc]') : (function(){

	var divs = (document.getElementById('commonAncestorElementIdGoesHere') || document).getElementsByTagName('div'),
		i = divs.length,
		result = [],
		div;
	while (i--){
		div = divs[i];
		if (div.id && div.id.match(/^csc/)){
			result.push(div);
		}
	}
	return result;
})();

console.log(divs);