javascript 实现一个可以拖动、变形的矩形框
目标：用 js 实现一个可以拖动、变形的矩形框。
源代码：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<style>
* {
margin: 0;
padding: 0
}
.box {
width: 300px;
height: 300px;
position: absolute;
top: 150px;
left: 150px;
}
/*四边*/
.box .t,
.box .b,
.box .l,
.box .r {
position: absolute;
z-index: 1;
background: #666;
}
.box .l,
.box .r {
width: 4px;
height: 100%;
cursor: col-resize;
}
.box .t,
.box .b {
width: 100%;
height: 4px;
cursor: row-resize;
}
.box .t {
top: 0;
}
.box .b {
bottom: 0;
}
.box .l {
left: 0;
}
.box .r {
right: 0;
}
/*四角*/
.box .tl,
.box .bl,
.box .br,
.box .tr {
width: 20px;
height: 20px;
position: absolute;
background: #fff;
border:1px solid #666;
z-index: 2;
cursor: nwse-resize
}
.box .tl,
.box .bl {
left: -5px;
}
.box .tr,
.box .br {
right: -5px;
}
.box .br,
.box .bl {
bottom: -5px;
}
.box .tl,
.box .tr {
top: -5px;
}
.box .tr,
.box .bl {
cursor: nesw-resize;
}
/*内核*/
.inner {
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<!-- 将边线的缩放也加了 -->
<div class="box" id="odiv">
<span class="r"></span>
<span class="l"></span>
<span class="t"></span>
<span class="b"></span>
<span class="br"></span>
<span class="bl"></span>
<span class="tr"></span>
<span class="tl"></span>
<div class="inner"></div>
</div>
<script>
window.onload = function () {
var oDiv = document.getElementsByTagName('div')[0];
// oDiv.style.width = '500px';
var aSpan = oDiv.getElementsByTagName('span');
for (var i = 0; i < aSpan.length; i++) {
dragFn(aSpan[i]);
}
function dragFn(obj) {
obj.onmousedown = function (ev) {
var oEv = ev || event;
oEv.stopPropagation();
var oldWidth = oDiv.offsetWidth;
var oldHeight = oDiv.offsetHeight;
var oldX = oEv.clientX;
var oldY = oEv.clientY;
var oldLeft = oDiv.offsetLeft;
var oldTop = oDiv.offsetTop;
document.onmousemove = function (ev) {
var oEv = ev || event;
let disY = (oldTop + (oEv.clientY - oldY)),
disX = (oldLeft + (oEv.clientX - oldLeft));
if(disX>oldLeft+oldWidth){
disX=oldLeft+oldWidth
}
if(disY>oldTop+oldHeight){
disY=oldTop+oldHeight
}
if (obj.className == 'tl') {
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px';
oDiv.style.height = oldHeight - (oEv.clientY - oldY) + 'px';
oDiv.style.left = disX + 'px';
oDiv.style.top = disY + 'px';
}
else if (obj.className == 'bl') {
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px';
oDiv.style.height = oldHeight + (oEv.clientY - oldY) + 'px';
oDiv.style.left = disX + 'px';
oDiv.style.bottom = oldTop + (oEv.clientY + oldY) + 'px';
}
else if (obj.className == 'tr') {
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px';
oDiv.style.height = oldHeight - (oEv.clientY - oldY) + 'px';
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px';
oDiv.style.top = disY + 'px';
}
else if (obj.className == 'br') {
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px';
oDiv.style.height = oldHeight + (oEv.clientY - oldY) + 'px';
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px';
oDiv.style.bottom = oldTop + (oEv.clientY + oldY) + 'px';
}
else if (obj.className == 't') {
oDiv.style.height = oldHeight - (oEv.clientY - oldY) + 'px';
oDiv.style.top = disY + 'px';
}
else if (obj.className == 'b') {
oDiv.style.height = oldHeight + (oEv.clientY - oldY) + 'px';
oDiv.style.bottom = disY + 'px';
}
else if (obj.className == 'l') {
oDiv.style.height = oldHeight + 'px';
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px';
oDiv.style.left = disX + 'px';
}
else if (obj.className == 'r') {
oDiv.style.height = oldHeight + 'px';
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px';
oDiv.style.right = disX + 'px';
}
};
document.onmouseup = function () {
document.onmousemove = null;
};
return false;
};
}
document.getElementById("odiv").onmousedown = function (ev) {
var oevent = ev || event;
oevent.preventDefault();
var distanceX = oevent.clientX - oDiv.offsetLeft;
var distanceY = oevent.clientY - oDiv.offsetTop;
document.onmousemove = function (ev) {
var oevent = ev || event;
oDiv.style.left = oevent.clientX - distanceX + 'px';
oDiv.style.top = oevent.clientY - distanceY + 'px';
};
document.onmouseup = function () {
document.onmousemove = null;
document.onmouseup = null;
};
}
};
</script>
</body>
</html>
效果图:
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