What's a cross-browser way to check if a JavaScript variable is a <form> DOM object?

var form = document.createElement('form');

(form.isDOMForm()) would evaluate开发者_JS百科 to true.

You mean this:

var form = document.createElement('form');
alert(form.nodeName);

More Info:

http://www.howtocreate.co.uk/tutorials/javascript/dombasics

Note that you can also use tagName but nodeName seems to be a better choice.