//获取屏幕大小
function setRange()
{
    var range = getRange();
    var table_main = document.getElementById("table_main");
    table_main.width = range.width;
    table_main.height = range.height;
}
function getRange()
{ 
    var top = document.documentElement.scrollTop; 
    var left = document.documentElement.scrollLeft; 
    var height = document.documentElement.clientHeight; 
    var width = document.documentElement.clientWidth;
    var scHeight = document.documentElement.scrollHeight; 
    var scWidth = document.documentElement.scrollWidth; 
    return {top:top ,left:left ,height:height ,width:width,scHeight:scHeight,scWidth:scWidth } ; 
}