function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

var clearedOnce = false;
addLoadEvent(function() {
	if( document.getElementById ) {
		document.getElementById('keywords').onfocus = function() {
			if( clearedOnce == false ) {
				this.value = '';
				clearedOnce = true;
			}			
		};
	}
});