finding elements ID on click

//create an array from classes
var jsClass = document.getElementsByClassName("jsClass");

//loop through the length of the array
for (var i = 0; i < jsClass.length; i++) {

    //assign a onclick event to each element
    jsClass[i].onclick = function() {
        //this will be the actual element.  So you can use this.id to get the element's id
        var thisId = this.id;
    }
}