JS拖拽事件，碰撞检测(碰撞变色效果)
百里业
<html>
<head>
<meta charset="utf-8" />
<title>碰撞检测</title>
<style>
.box {
width:100px;
height:100px;
background:red;
position:absolute;
}
.box1 {
width:200px;
height:200px;
background:yellow;
position:absolute;
top:50%;
left:50%;
margin-top:-100px;
margin-left:-100px;
}
</style>
</head>
<body onkeydown="show()">
<div class="box1"></div>
<div class="box"></div>
</body>
<script>
window.onload = function() {
var box = document.getElementsByClassName("box")[0];
var box1 = document.getElementsByClassName("box1")[0];
box.onmousedown = function(ev) {
var ev = window.event || ev;
var left = ev.clientX - box.offsetLeft;
var top = ev.clientY - box.offsetTop;
if (box.setCapture) {
box.setCapture();
}
document.onmousemove = function() {
var ev = window.event || ev;
box.style.left = ev.clientX - left + "px";
box.style.top = ev.clientY - top + "px";
//获取运动div的left和top
var l = ev.clientX - left;
var t = ev.clientY - top;
//获取参考div的left和top值
var L = box1.offsetLeft;
var T = box1.offsetTop;
if (l + box.offsetWidth < L || t + box.offsetHeight < T || L + box1.offsetWidth < l || T + box1.offsetHeight < t) {
box1.style.background = "";
} else {
box1.style["background"] = "orange";
}
}
box.onmouseup = function() {
document.onmousemove = box.onmouseup = "";
if (box.releaseCapture) {
box.releaseCapture();
}
}
return false;
}
}
</script>
</html>
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