function cmb_selectByValue(elementId, valueToSelect)
	{
		var comboElement = document.getElementById(elementId);
		for (var i = 0; i < comboElement.options.length; i++) {
	   		if ( comboElement.options[i].value == valueToSelect )
	   			comboElement.options[i].selected = "1";
	   }
	}
	
	function cmb_clear(elementId)
	{
		var comboElement = document.getElementById(elementId);
		comboElement.length=0;
	}
	
	function cmb_newOption(elementId, cvalue, ctext)
	{
		var comboElement = document.getElementById(elementId);
		comboElement.options[comboElement.length] = new Option(ctext, cvalue);
	}
	
	function cmb_removeOption(elementId)
	{
		var comboElement = document.getElementById(elementId);
		if ( comboElement.selectedIndex == -1 )
			return false;
		else
			for( i=comboElement.options.length-1; i>=0; i-- ) 
			{
				if( comboElement.options[i].selected )
					comboElement.remove(i);
			}
		return true;
	}