1、取得对象的坐标

function getElementPos(elementId) {
 var ua = navigator.userAgent.toLowerCase();
 var isOpera = (ua.indexOf('opera') != -1);
 var isIE = (ua.indexOf('msie') != -1 && !isOpera);
 var el = document.getElementById(elementId);
 
 if(el.parentNode === null || el.style.display == 'none')
 {
  return false;
 }
 
 var parent = null;
 var pos = [];
 var box;
 
 if(el.getBoundingClientRect)
 {
  box = el.getBoundingClientRect();
  var scrollTop = Math.max(document.documentElement.scrollTop, document.body.scrollTop);
  var scrollLeft = Math.max(document.documentElement.scrollLeft, document.body.scrollLeft);
  return {x:box.left + scrollLeft, y:box.top + scrollTop};
 }
 else if(document.getBoxObjectFor)
 {
  box = document.getBoxObjectFor(el);
  var borderLeft = (el.style.borderLeftWidth)?parseInt(el.style.borderLeftWidth):0;
  var borderTop = (el.style.borderTopWidth)?parseInt(el.style.borderTopWidth):0;
  pos = [box.x - borderLeft, box.y - borderTop];
 }
 else
 {
  pos = [el.offsetLeft, el.offsetTop];
  parent = el.offsetParent;
  if (parent != el) {
   while (parent) {
    pos[0] += parent.offsetLeft;
    pos[1] += parent.offsetTop;
    parent = parent.offsetParent;
   }
  }
 
  if (ua.indexOf('opera') != -1|| ( ua.indexOf('safari') != -1 && el.style.position == 'absolute' ))
  {
   pos[0] -= document.body.offsetLeft;
   pos[1] -= document.body.offsetTop;
  }
 
 }
 
 if (el.parentNode) {
  parent = el.parentNode;
 }else {
  parent = null;
 }
 
 while (parent && parent.tagName != 'BODY' && parent.tagName != 'HTML')
 {
  pos[0] -= parent.scrollLeft;
  pos[1] -= parent.scrollTop;
 
  if (parent.parentNode) {
   parent = parent.parentNode;
  }else { parent = null; }
  
 }

 return {x:pos[0], y:pos[1]};
};

2、取得页面编码
function getCode() {
 var metas = document.getElementsByTagName("meta");
 var strMeta = new String();
 var strTemp;
 for (var i = 0; i < metas.length; i++) {
  strTemp = metas[i].name + "=" + metas[i].content + " ";
  strMeta = strMeta.concat(strTemp);
 }
 strMeta = strMeta.toLowerCase();
 if (parseInt(strMeta.indexOf("utf-8")) != -1){
  return "utf-8";
 }
 return "gb2312";
};

方法一：利用正则替换

 

方法二：利用文本替换，目前一些类似点睛的那种文字富媒体广告的实现都是基于该方法