Question

How can I always extract the number 11 in all these cases.

id="section-11" 
id="test-11"
id="something-11"

I do $(this).attr('id'); then what do I do next?

Answer 1

Many ways to achieve that, one way is to use .split() like:

var id = "section-11";

var number = id.split(/-/)[ 1 ];

alert( number );  // 11