Regular expression to get a class name from html

Question

I know my question might look like a duplication for this question, but its not
I am trying to match a class name inside html text that comes from the

Answer 1

Use the browser to your advantage:

var str = '
\
\
\
';

var wrapper = document.createElement('div');
wrapper.innerHTML = str;

var elements = wrapper.getElementsByClassName('b');

if (elements.length) {
    // there are elements with class b
}

Demo

Btw, getElementsByClassName() is not very well supported in IE until version 9; check this answer for an alternative.