function ddMenu(id){
  var h = document.getElementById(id);
  var c = document.getElementById(id+'_menu');
  c.style.display = 'block';
  

  var scrolltop = GetScrollTop();

  oRect = h.getBoundingClientRect();
  c.style.left = oRect.left-20  + "px";
  c.style.top = oRect.top + GetScrollTop()+10+ "px";
}
function hiddMenu(id) {
    var c = document.getElementById(id + '_menu');
    c.style.display = 'none';
}
function getStyle(ele,value) {/*-----  获取元素的真实style  -----*/
    var rs;
    if(ele.style[value]) {
        rs = ele.style[value];
    }else if(window.getComputedStyle) {
        value=value.replace(/([A-Z])/g,"-$1");
        rs = window.getComputedStyle(ele,'').getPropertyValue(value);
    }else if(ele.currentStyle) {
        rs = ele.currentStyle[value];
    }else {
        return null;
    }
    return rs;
}
var w3c = (document.getElementById) ? true : false;
var agt = navigator.userAgent.toLowerCase();
var ie = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1) && (agt.indexOf("omniweb") == -1));

function IeTrueBody() {
    return (document.compatMode && document.compatMode != "BackCompat") ? document.documentElement : document.body;
}

function GetScrollTop() {
    return ie ? IeTrueBody().scrollTop : window.pageYOffset;
}