event binding

event binding

When i hit enter in the text box or click search button, i am not going into that forms submit.

JS
<script language="javascript" type="text/javascript">
   $("#search_form").submit(function()
   {
      alert(1)
      var searchValue    = ''+$('#q').val();
      var defaultValue    = 'Enter Keywords';
      alert(2)
      if(defaultValue.toUpperCase() == searchValue.toUpperCase() || searchValue.toUpperCase() == ''){
         $("#msgboxGoogleSearch").fadeTo(200,0.1,function() //start fading the messagebox
         {
           //add message and change the class of the box and start fading
           $(this).html('No search provided...').addClass('messageboxerror').fadeTo(900,1);
         });
         return false;
      }
      else{
         return true;
      }
   });
</script>


HTML
<form id="search_form" name="search_form" method="GET" action="http://googlebox.com/search">
       <input type="text" id="q" name="q" value="Enter Keywords" class="textBox swap_value">
       <input type="image" src="/images/structure/btn_search_boxYellow.gif" width="20" height="17" class="searchButton" id="GoogleSearch" name="GoogleSearch" alt="Search" title="Search" />
      
   </form>
   <span id="msgboxGoogleSearch"></span>


Thank you