gistfile1.js

<script type="text/javascript" charset="utf-8">
  var search_constant = "Enter a diagnosis name ...";
  function setSearchConstant(){
    if("" == $("#search_term").val())
    {
      $("#search_term").val(search_constant);
    }
  }
  $(document).ready(function(){
    
    setSearchConstant();
    
    $("#search_term").click(function(){
      if(search_constant == $("#search_term").val()) {
        $("#search_term").val("");
      }
    });
    
    $("#search_term").blur(function(){
      setSearchConstant();
    })
  })
</script>