I know you can do this, but every time I Google it I get how to select all elements of a certain tag.
So, e.g.:
alert($('#my-wrapper').someJSMethod());
{...}
<div id="my-wrapper"></div>
Would alert "DIV" actually. I'm selecting elements with jQuery by the way.
You can do this:
alert($('#my-wrapper').get(0).nodeName);
//or:
alert($('#my-wrapper')[0].nodeName);
Or, no need for jQuery:
alert(document.getElementById('my-wrapper').nodeName);
$('#my-wrapper')[0].tagName
nodeName is better way to do it.
tagName is preferable, if it's definitely a tag name you want. It's marginally more readable and if you make a mistake it's slightly more obvious in that you get undefined instead of a fairly-arbitrary string for other nodeTypes. (It's not as obvious as it should be, though, since undefined is a horrible wrongness. A reasonable language would have raised an exception.) I completely disagree with the linked site that #text is somehow preferable to undefined, and feel that on IE, nodeName's failure case on Document is worse than tagName's unexpected existence on Comment.
nodeName or tagName. Beyond that, it's a matter of personal taste. I tend to use nodeName, for no particular reason.