function ChangeText() 
{
  document.getElementById('ctl00_RegionHeader_Header_SearchTextBox').value = "";   
} 

function clickButton(e, buttonid){ 

      var evt = e ? e : window.event;

      var bt = document.getElementById(buttonid);

  if (bt){ 

        var browser =navigator.appName;
        
        if(browser =="Microsoft Internet Explorer")
        { 
              
              if (evt.keyCode == 13)
              { 

                    bt.click(); 

                    return false; 

              } 
        }
       // else
        //{
          //    if(evt.which == 13)
            //  {
                   // bt.click(); 
             // }
        //}
          

      } 

}