window.onload=function(){

var rightDiv=document.getElementById("right");

var mainDiv=document.getElementById("main");

var ifKeyDown=false;

rightDiv.onmousedown=function(){

ifKeyDown=true;

}

window.onmouseup=function(){

ifKeyDown=false;

}

window.onmousemove=function(e){

if(ifKeyDown==true)

{

var x= e.clientX;//鼠标x左边

var widthBefore=mainDiv.offsetWidth-2;

var addWidth=x - getPosition(mainDiv).left - widthBefore;//鼠标移动后增加的宽度

mainDiv.style.width=addWidth + widthBefore +"px";

}

}

}

//获取元素相对于屏幕左边的距离；

function getPosition(node)

{

var left=node.offsetLeft;

var parent=node.offsetParent;

var top=node.offsetTop;

while(parent != null)

{

left +=parent.offsetLeft;

top +=parent.offsetTop;

parent=parent.offsetParent;

}

return (left,top);

}