tabs() : when ENTER is pressed in an <input>, jumps to another Tab

tabs() : when ENTER is pressed in an <input>, jumps to another Tab

I have a search field within a third tab using the .tabs() UI.

As I want, the <input> responds to  person pressing on ENTER.
(The alert "pressing enter worked' pops up.) However, it also jumps to the first tab.

I don't know why?

Thanks for any help in advance. Sushi

HTML
  1. <input type="text" name="search" id="search" value="Search" onFocus=this.value=''></input>     

jQuery
  1.   $('#search').bind('keyup', function (e) {
  2.             var key = e.keyCode || e.which;
  3.             if (key === 13) {
  4.                     alert("pressing enter worked");  
  5.                 };
  6.         });