function checkVar(str){
		if(str<=0)str = 24 + str;
		var tmpvar = str.toString();
		return '0000'.substring(0,2-tmpvar.length)+tmpvar;
	}
	
	function fillTime(){
		var systime = new Date();
		document.getElementById('BeiJing').innerHTML = checkVar(systime.getHours())+':'+checkVar(systime.getMinutes())+':'+checkVar(systime.getSeconds());
		document.getElementById('London').innerHTML = checkVar(systime.getHours()-8)+':'+checkVar(systime.getMinutes())+':'+checkVar(systime.getSeconds());
		document.getElementById('NewYork').innerHTML = checkVar(systime.getHours()-13)+':'+checkVar(systime.getMinutes())+':'+checkVar(systime.getSeconds());
		document.getElementById('Sydney').innerHTML = checkVar(systime.getHours()-22)+':'+checkVar(systime.getMinutes())+':'+checkVar(systime.getSeconds());
		setTimeout('fillTime()',1000);
	}