本篇文章为大家展示了div标签的resize事件怎么利用JavaScript进行监听，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
具体实现
/**
* Created by taozh on 2017/5/6.
* taozh2982@gmail.com
*/
var EleResize = {
_handleResize: function (e) {
var ele = e.target || e.srcElement;
var trigger = ele.__resizeTrigger__;
if (trigger) {
var handlers = trigger.__z_resizeListeners;
if (handlers) {
var size = handlers.length;
for (var i = 0; i < size; i++) {
var h = handlers[i];
var handler = h.handler;
var context = h.context;
handler.apply(context, [e]);
}
}
}
},
_removeHandler: function (ele, handler, context) {
var handlers = ele.__z_resizeListeners;
if (handlers) {
var size = handlers.length;
for (var i = 0; i < size; i++) {
var h = handlers[i];
if (h.handler === handler && h.context === context) {
handlers.splice(i, 1);
return;
}
}
}
},
_createResizeTrigger: function (ele) {
var obj = document.createElement('object');
obj.setAttribute('style',
'display: block; position: absolute; top: 0; left: 0; height: 100%; width: 100%; overflow: hidden;opacity: 0; pointer-events: none; z-index: -1;');
obj.onload = EleResize._handleObjectLoad;
obj.type = 'text/html';
ele.appendChild(obj);
obj.data = 'about:blank';
return obj;
},
_handleObjectLoad: function (evt) {
this.contentDocument.defaultView.__resizeTrigger__ = this.__resizeElement__;
this.contentDocument.defaultView.addEventListener('resize', EleResize._handleResize);
}
};
if (document.attachEvent) {//ie9-10
EleResize.on = function (ele, handler, context) {
var handlers = ele.__z_resizeListeners;
if (!handlers) {
handlers = [];
ele.__z_resizeListeners = handlers;
ele.__resizeTrigger__ = ele;
ele.attachEvent('onresize', EleResize._handleResize);
}
handlers.push({
handler: handler,
context: context
});
};
EleResize.off = function (ele, handler, context) {
var handlers = ele.__z_resizeListeners;
if (handlers) {
EleResize._removeHandler(ele, handler, context);
if (handlers.length === 0) {
ele.detachEvent('onresize', EleResize._handleResize);
delete ele.__z_resizeListeners;
}
}
}
} else {
EleResize.on = function (ele, handler, context) {
var handlers = ele.__z_resizeListeners;
if (!handlers) {
handlers = [];
ele.__z_resizeListeners = handlers;
if (getComputedStyle(ele, null).position === 'static') {
ele.style.position = 'relative';
}
var obj = EleResize._createResizeTrigger(ele);
ele.__resizeTrigger__ = obj;
obj.__resizeElement__ = ele;
}
handlers.push({
handler: handler,
context: context
});
};
EleResize.off = function (ele, handler, context) {
var handlers = ele.__z_resizeListeners;
if (handlers) {
EleResize._removeHandler(ele, handler, context);
if (handlers.length === 0) {
var trigger = ele.__resizeTrigger__;
if (trigger) {
trigger.contentDocument.defaultView.removeEventListener('resize', EleResize._handleResize);
ele.removeChild(trigger);
delete ele.__resizeTrigger__;
}
delete ele.__z_resizeListeners;
}
}
}
}
测试代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Resize</title>
<script src="./EleResize.js"></script>
<style>
html, body {
margin: 0;
padding: 0;
width: 100%;
height: 100%;
}
#resizeDiv {
width: 60%;
height: 60%;
border: 1px solid red;
margin: 20px;
}
button {
margin: 20px 20px 0;
}
</style>
</head>
<body>
<button onclick="addListener()">addListener</button>
<button onclick="removeListener()">removeListener</button>
<button onclick="resize()">resize</button>
<div id="resizeDiv"></div>
<script>
var resizeDiv = document.getElementById('resizeDiv');
function resize() {
resizeDiv.style.width = "200px";
}
var listener = function () {
console.log("resize");
};
function addListener() {
EleResize.on(resizeDiv, listener);
}
function removeListener() {
EleResize.off(resizeDiv, listener)
}
</script>
</body>
</html>
原理
这里的具体实现分两类，
- ie9-10
默认支持div的resize事件，可以直接通过div.attachEvent('onresize', handler);的方式实现
- 其它浏览器
通过在div中添加一个内置object元素实现监听。
设置object元素的style使其填充满div，这样当div的size发生变化时，object的size也会发生变化。
然后监听object元素的contentDocument.defaultView(window对象)的resize事件。
上述内容就是div标签的resize事件怎么利用JavaScript进行监听，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注本站行业资讯频道。
