function getstyle(elem,name){
if(elem.style[name]){
return elem.style[name];
}else if(elem.currentstyle){
return elem.currentstyle[name];
}else if(document.defaultview && document.defaultview.getcomputedstyle){
name = name.replace(/([a-z])/g,-$1);
name = name.tolowercase();
var s = document.defaultview.getcomputedstyle(elem,);
return s && s.getpropertyvalue(name);
}else{
return null;
}
}
//两个确定元素相对于整个文档的x和y位置的辅助位置
function pagex(elem){
return elem.offsetparent?
elem.offsetleft+pagex(elem.offsetparent):
elem.offsetleft;
}
function pagey(elem){
return elem.offsetparent?
elem.offsettop+pagey(elem.offsetparent):
elem.offsettop;
}
//确定元素相对于父亲的位置的两个函数
function parentx(elem){
return elem.parentnode == elem.offsetparent?
elem.offsetleft:
pagex(elem)-pagex(elem.parentnode);
}
function parenty(elem){
return elem.parentnode==elem.offsetparent?
elem.offsettop:
pagey(elem)-pagey(elem.parentnode);
}
//确定元素相对于它的css容器的位置
function posx(elem){
return parseint(getstyle(elem,left));
}
function posy(elem){
return parseint(getstyle(elem,top));
}
//设置元素x和y位置(与当前位置无关)的函数
function setx(elem,pos){
elem.style.left = pos+px;
}
function sety(elem,pos){
elem.style.top = pos+px;
}
//调整元素相对于当前位置的距离的函数
function addx(elem,pos){
setx(posx(elem)+pos);
}
function addy(elem,pos){
sety(posy(elem)+pos);
}
//获取元素当前的高度和宽度
function getheight(elem){
return parseint(getstyle(elem,'height'));
}
function getwidth(elem){
return parseint(getstyle(elem,'width'));
}
//即是元素隐藏，也能分别获取它潜在的完整高度和宽度的两个函数
function fullheight(elem){
if(getstyle(elem,'display')!='none'){
return elem.offsetheight||getheight(elem);
}
var old = resetcss(elem,{
display:'',
visibility:'hidden',
position:'absolute'
});
var h = elem.clientheight||getheight(elem);
restorecss(elem,old);
return h;
}
function fullwidth(elem){
if(getstyle(elem,'display')!='none'){
return elem.offsetwidth || getwidth(elem);
}
var old = resetcss(elem,{
display:'',
visibility:'hidden',
position:'absolute'
});
var w = elem.clientwidth || getwidth(elem);
restorecss(elem,old);
return w;
}
function resetcss(elem,prop){
var old = [];
for(var i in prop){
old[i] = elem.style[i];
elem.style[i] = prop[i];
}
return old;
}
function restorecss(elem,prop){
for(var i in prop){
elem.style[i] = prop[i];
}
}
//使用css的display属性来切换元素可见性的一组函数
function hide(elem){
var curdisplay = getstyle(elem,'display');
if(curdisplay != 'none'){
elem.$olddisplay= curdisplay;
}
elem.style.display = 'none';
}
function show(elem){
elem.style.display = elem.$olddisplay ||'';
}
//设置元素的透明度
function setopacity(elem,level){
if(elem.filters){
elem.style.filters = 'alpha(opacity='+level+')';
}else{
elem.style.opacity = level/100;
}
}