
var kfC = document.getElementById('kf_container');
var z_top = kfC.offsetTop;
/*
window.onscroll = function(){
	setTimeout('z_zxkf_scroll()',350);
}
*/

var z_zxkf_setTimeout = function(){
	setTimeout('z_zxkf_scroll()',350);
}
function z_zxkf_scroll(){
	var scroTop, cur_top, step, flag, timer = 80, multiplier = 15, little_step = 8;
	scroTop = document.documentElement.scrollTop || document.body.scrollTop;
	cur_top = kfC.offsetTop;
	step = scroTop + z_top - cur_top;//移动距离 = 页面滚动距离 + 客服容器与页面顶部原来的距离 - 客服容器与页面顶部现在的距离
	flag = step > 0 ? 1 : -1;
	step = Math.abs(step);
	step = step > little_step*multiplier ? little_step : step/multiplier;
	if(step < 1){
		kfC.style.top = scroTop + z_top + 'px';
	}else{
		kfC.style.top = (cur_top + flag*step) + 'px';
		setTimeout('z_zxkf_scroll()',timer);
	}
}


if(kfC.style.display == 'block'){
	if (navigator.appVersion.indexOf("MSIE") != -1){   // IE用attachEvent
		window.attachEvent('onscroll', z_zxkf_setTimeout);
	}else{   // 非IE用addEventListener
		document.addEventListener("scroll", z_zxkf_setTimeout, false); 
	}
}