Enable Backspace With Jquery Oninput Event Within The Text On An Input Form?

I have an input form that has a jQuery event applied to it that creates square brackets around the users input. The issue is that the event prevents the ability to use backspace to

Solution 1:

 function test(obj,e) {  
      if(!(e.which == 8)){
           var oldVal = obj.val().replace(/\[/g,'');
           oldVal = oldVal.replace(/\]/g,'');
           var val = '[' + oldVal + ']';
           obj.val(val);
      }
 }

and pass event as parameter ..

 <input class="text-box" onkeyup="test($(this),event)">