window.οnlοad=
function ()
{
var oDiv=document.getElementById('div1'
);
var lastX=0
;
var lastY=0
;
oDiv.onmousedown=
function (ev)
{
var oEvent=ev||
event;
var disX=oEvent.clientX-
oDiv.offsetLeft;
var disY=oEvent.clientY-
oDiv.offsetTop;
document.onmousemove=
function (ev)
{
var oEvent=ev||
event;
var l=oEvent.clientX-
disX;
var t=oEvent.clientY-
disY;
oDiv.style.left=l+'px'
;
oDiv.style.top=t+'px'
;
iSpeedX=l-
lastX;
iSpeedY=t-
lastY;
lastX=
l;
lastY=
t;
document.title='x:'+iSpeedX+', y:'+
iSpeedY;
};
document.onmouseup=
function ()
{
document.onmousemove=
null;
document.onmouseup=
null;
startMove();
};
clearInterval(timer);
};
};
var timer=
null;
var iSpeedX=0
;
var iSpeedY=0
;
function startMove()
{
clearInterval(timer);
timer=setInterval(
function (){
var oDiv=document.getElementById('div1'
);
iSpeedY+=3
;
var l=oDiv.offsetLeft+
iSpeedX;
var t=oDiv.offsetTop+
iSpeedY;
if(t>=document.documentElement.clientHeight-
oDiv.offsetHeight)
{
iSpeedY*=-0.8
;
iSpeedX*=0.8
;
t=document.documentElement.clientHeight-
oDiv.offsetHeight;
}
else if(t<=0
)
{
iSpeedY*=-1
;
iSpeedX*=0.8
;
t=0
;
}
if(l>=document.documentElement.clientWidth-
oDiv.offsetWidth)
{
iSpeedX*=-0.8
;
l=document.documentElement.clientWidth-
oDiv.offsetWidth;
}
else if(l<=0
)
{
iSpeedX*=-0.8
;
l=0
;
}
if(Math.abs(iSpeedX)<1
)
{
iSpeedX=0
;
}
if(Math.abs(iSpeedY)<1
)
{
iSpeedY=0
;
}
if(iSpeedX==0 && iSpeedY==0 && t==document.documentElement.clientHeight-
oDiv.offsetHeight)
{
clearInterval(timer);
alert('停止'
);
}
else
{
oDiv.style.left=l+'px'
;
oDiv.style.top=t+'px'
;
}
document.title=
iSpeedX;
}, 30
);
}
转载于:https://www.cnblogs.com/ggbd-lie/archive/2012/11/18/2776104.html
相关资源：JavaScript拖拽、碰撞、重力及弹性运动实例分析
