网上搜的资料，源码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<style>
* {
margin: 0;
padding: 0
} .box {
position: absolute;
top: 100px;
left: 100px;
} /*四边*/
.box .t,
.box .b,
.box .l,
.box .r {
position: absolute;
z-index: 1;
background:#666;
} .box .l,
.box .r {
width: 10px;
height: 100%;
cursor: col-resize;
} .box .t,
.box .b {
width: 100%;
height: 10px;
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: #CCC;
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;
} /*图片*/
img {
width: 100%;
height: 100%;
}
</style>
<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; 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; if (obj.className == 'tl') {
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px';
oDiv.style.height=oldHeight-(oEv.clientY-oldY)+'px';
oDiv.style.left = oldLeft + (oEv.clientX - oldX) + 'px';
oDiv.style.top = oldTop + (oEv.clientY - oldY) + '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 = oldLeft + (oEv.clientX - oldX) + '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 = oldTop + (oEv.clientY - oldY) + '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 = oldTop + (oEv.clientY - oldY) + 'px';
}
else if (obj.className == 'b') {
oDiv.style.height = oldHeight + (oEv.clientY - oldY)+'px';
oDiv.style.bottom = oldTop - (oEv.clientY + oldY) + 'px';
}
else if (obj.className == 'l') {
oDiv.style.height = oldHeight + 'px';
oDiv.style.width = oldWidth - (oEv.clientX - oldX) + 'px';
oDiv.style.left = oldLeft + (oEv.clientX - oldX) + 'px';
}
else if (obj.className == 'r') {
oDiv.style.height = oldHeight + 'px';
oDiv.style.width = oldWidth + (oEv.clientX - oldX) + 'px';
oDiv.style.right = oldLeft - (oEv.clientX - oldX) + 'px';
}
}; document.onmouseup = function () {
document.onmousemove = null;
};
return false;
};
} };
</script>
</head> <body>
<div class="box">
<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>
<img src="https://gss0.bdstatic.com/70cFsjip0QIZ8tyhnq/img/iknow/730-350-0.jpg">
</div>
</body>
</html>