var move=document.getElementsByClassName("page1_2")[0];
var startX=0;
var startY=0;
var x=0;
var y=0;
var off = 0;
move.onmousedown=function (e) {
var e = e || event;
off=1;
startX = this.offsetLeft;
startY = this.offsetTop;
x=e.pageX-startX;
y=e.pageY-startY;
};
document.onmousemove=function (e) {
var e = e || event;
if (!off)return;
var x1=e.pageX-x;
var y1=e.pageY-y;
if(x1<0){
x1=0
}
if(y1<0){
y1=0
}
if(x1>window.innerWidth-move.offsetWidth){
x1=window.innerWidth-move.offsetWidth
}
if(y1>window.innerHeight-move.offsetHeight){
y1=window.innerHeight-move.offsetHeight
}
move.style.left=x1+'px';
move.style.top=y1+"px";
};
document.onmouseup=function (e) {
off = 0;
};
window.onload=function(){
var q1=document.getElementById('q1');
var disx=0;
var disy=0;
q1.onmousedown=function(ev){
var oEvent=ev||event;
disx=oEvent.clientX-q1.offsetLeft;
disy=oEvent.clientY-q1.offsetTop;
document.onmousemove=function(ev){
var oEvent=ev||event;
var l=oEvent.clientX-disx;
var t=oEvent.clientY-disy;
if(l<0){
l=0
}else if(l>document.documentElement.clientWidth-q1.offsetWidth){
l=document.documentElement.clientWidth-q1.offsetWidth
}
if(t<0){
t=0
}
else if(t>document.documentElement.clientHeight-q1.offsetHeight){
t=document.documentElement.clientHeight-q1.offsetHeight
}
q1.style.left=l+'px';
q1.style.top=t+'px';
};
document.onmouseup=function(){
document.onmousemove=null;
document.onmouseup=null;
}
};
return false;//阻止默认行为，火狐浏览器第二次拖拽有空div
}