firstElementChild doesn't work in Internet Explorer 7…what are my options?

Question

Consider the JavaScript below:

var v;
if (this.children.length > 0) {
    v = this.firstElementChild.value;
}

This works in modern versions

Answer 1

If your code is in an event handler and the function is bound with "attachEvent" the "this" keyword is bound to the "window" object and not the HTMLElement. Try:

function doSomething(e) {
    var targ;
    if (!e) var e = window.event;
    if (e.target) targ = e.target;
    else if (e.srcElement) targ = e.srcElement;
    if (targ.nodeType == 3) // defeat Safari bug
        targ = targ.parentNode;
}

Check http://www.quirksmode.org/js/events_properties.html.