jQuery / Get numbers from a string

You can get it like this:

var suffix = 'comment_like_123456'.match(/\d+/); // 123456

With respect to button:

$('.comment_like').click(function(){
  var suffix = this.id.match(/\d+/); // 123456
});

You can try this. it will extract all number from any type of string.

var suffix = 'comment_like_6846511';
alert(suffix.replace(/[^0-9]/g,''));

DEMO