Question

I use this code to get value from an input box:

var suggest_type = document.getElementById('ac-type').value;

Now I need to apply my js code on several other pages. I heard that it’s not nice to repeat an ID on one website. So, I’m thinking to change to use class like this:

var suggest_type = document.getElementByClass('ac-type').value;

This doesn’t get the value. How can I use class to get value?

Answer 1

You should stick with using ID’s – they only have to be unique within a page.

If you must use classes, you need to use getElementsByClassName():

var elems = document.getElementsByClassName('ac-type');
var value = elems[0].value;

However this function is not well supported on older browsers, which is another good reason to stick with IDs.