代码：
function drag(t,p){
var point = p || null,
target = t || null,
resultX = 0,
resultY = 0;
(!point)? point = target : ''; //如果没有拖动点，则拖动点默认为整个别拖动元素
function getPos(t){
var offsetLeft = 0,
offsetTop = 0,
offsetParent = t;
while(offsetParent){
offsetLeft+=
