javascript中级--事件--拖拽
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#div1 {
width: 100px;
height: 100px;
background: red;
position: absolute;
}
</style>
<script>
window.onload = function() {
var oDiv = document.getElementById('div1');
var disX = 0;
var disY = 0;
oDiv.onmousedown = function(ev) {
var oEvent = ev || event;
disX = oEvent.clientX - oDiv.offsetLeft;
disY = oEvent.clientY - oDiv.offsetTop;
// alert(disX);
document.onmousemove = function(ev) {
var oEvent = ev || event;
var l = oEvent.clientX - disX;
var y = oEvent.clientY - disY;
if (l < 0) {
l = 0;
} else if (l > document.documentElement.clientWidth - oDiv.offsetWidth) {
l = document.documentElement.clientWidth - oDiv.offsetWidth;
}
if (y < 0) {
y = 0;
} else if (y > document.documentElement.clientHeight - oDiv.offsetHeight) {
y = document.documentElement.clientHeight - oDiv.offsetHeight;
}
oDiv.style.left = l + 'px';
oDiv.style.top = y + 'px';
}
document.onmouseup = function() {
document.onmousemove = null;
document.onmouseup = null;
}
return false;
}
}
</script>
</head>
<body>
<div id="div1">
</div>
</body>
</html>
