Question

I’d like to make a function to the effect of:

function supportsElem(tagName) {
   // returns boolean
}

where:

supportsElem("div") // true 
supportsElem("randomtext") // false

What the easiest way to do that?

Answer 1

Just a guess, cause i’ve never had to care about this. But it’d seem to me you could create the element and then check to make sure it acts like it should. For example, that it has certain properties, or that its constructor is right (or at least, isn’t the same as a generic unsupported element would have).

An example of the constructor check (untested):

// pick a name that'll never be an element 
var generic_element = document.createElement('randomtext');

var tagName_to_check = document.createElement('div');
if (tagName_to_check.constructor === generic_element.constructor) {
    // the browser treats the node as a generic element, rather than
    // (eg) a DivElement
    // so it's probably unsupported
}