function cmnSwitch_class( eOn, sClass_name, sInstead ){
	if( cmnMatch_class( eOn, sClass_name ) ){
		cmnSet_class( eOn, sInstead, sClass_name );
	}else{
		cmnSet_class( eOn, sClass_name, sInstead );
	}
}



function cmnSet_class( eOn, sClass_name, sInstead ){
	if( eOn ){
		sClass_name = ( sClass_name.length ) ? sClass_name.replace( /(^\s+|\s+$)/, "" ) : "";
		if( eOn.className.length ){
			var sOld = sClass_name;
			if( sInstead && sInstead.length ){
				sInstead = sInstead.replace( /\s+(\S)/g, "|$1" );
				if( sOld ){
					sOld += "|";
				}
				sOld += sInstead;
			}
			eOn.className = eOn.className.replace( new RegExp("(^|\\s+)(" + sOld +")($|\\s+)", "g"), "$1" );
		}
		eOn.className += ( eOn.className.length && sClass_name ? " " : "" ) + sClass_name;
	}
}

function cmnMatch_class( eOn, sClass_name ){
	return ( sClass_name && eOn.className && eOn.className.length && eOn.className.match( new RegExp("(^|\\s+)(" + sClass_name +")($|\\s+)") ) );
}