几个JS方法

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";
};