트림 함수

  <script>
	function trim(str){
		var count = str.length;
		var len = count;                        
		var st = 0;         
		while ((st < len) && (str.charAt(st) <= ' ')) {
			st++;
		}        
		while ((st < len) && (str.charAt(len - 1) <= ' ')) {
			len--;
		}       
		return ((st > 0) || (len < count)) ? str.substring(st, len) : str ;    
	} 
  </script>