对于div元素的Onresize？

Question

Visual Studio突出显示onresize了我的div标记属性,并说它不是HTML5的有效属性.这是真的？我应该用什么呢？这种情况似乎有点愚蠢.

Answer 1

Microsoft的Internet Explorer支持onresize所有HTML元素.在所有其他浏览器中,onresize仅在window对象上可用. https://developer.mozilla.org/en-US/docs/Web/API/Window.onresize

如果你想div在所有浏览器中使用onresize,请检查:

http://marcj.github.io/css-element-queries/

该库有一个ResizeSensor可用于resize检测的类.

Answer 2

将以下CSS和JavaScript添加到您的页面,并使用addResizeListener和removeResizeListener方法来监听元素大小更改(博客文章了解更多详细信息:http://www.backalleycoder.com/2013/03/18/cross-browser-event- based-element-resize-detection /):

调整传感器CSS的大小

.resize-triggers {
    visibility: hidden;
}

.resize-triggers, .resize-triggers > div, .contract-trigger:before {
  content: " ";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  overflow: hidden;
}

.resize-triggers > div {
  background: #eee;
  overflow: auto;
}

.contract-trigger:before {
  width: 200%;
  height: 200%;
}

调整事件方法的大小

以下是启用调整大小事件监听所需的JavaScript.前两个函数是主addResizeListener和removeResizeListener方法中使用的先决条件.

(function(){

var attachEvent = document.attachEvent;

if (!attachEvent) {
    var requestFrame = (function(){
      var raf = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame ||
                function(fn){ return window.setTimeout(fn, 20); };
      return function(fn){ return raf(fn); };
    })();

    var cancelFrame = (function(){
      var cancel = window.cancelAnimationFrame || window.mozCancelAnimationFrame || window.webkitCancelAnimationFrame ||
                   window.clearTimeout;
      return function(id){ return cancel(id); };
    })();

    function resetTriggers(element){
        var triggers = element.__resizeTriggers__,
            expand = triggers.firstElementChild,
            contract = triggers.lastElementChild,
            expandChild = expand.firstElementChild;
        contract.scrollLeft = contract.scrollWidth;
        contract.scrollTop = contract.scrollHeight;
        expandChild.style.width = expand.offsetWidth + 1 + 'px';
        expandChild.style.height = expand.offsetHeight + 1 + 'px';
        expand.scrollLeft = expand.scrollWidth;
        expand.scrollTop = expand.scrollHeight;
    };

    function checkTriggers(element){
      return element.offsetWidth != element.__resizeLast__.width ||
             element.offsetHeight != element.__resizeLast__.height;
    }

    function scrollListener(e){
        var element = this;
        resetTriggers(this);
        if (this.__resizeRAF__) cancelFrame(this.__resizeRAF__);
        this.__resizeRAF__ = requestFrame(function(){
            if (checkTriggers(element)) {
                element.__resizeLast__.width = element.offsetWidth;
                element.__resizeLast__.height = element.offsetHeight;
                element.__resizeListeners__.forEach(function(fn){
                    fn.call(element, e);
                });
            }
        });
    };
}

window.addResizeListener = function(element, fn){
    if (attachEvent) element.attachEvent('resize', fn);
    else {
        if (!element.__resizeTriggers__) {
            if (getComputedStyle(element).position == 'static') element.style.position = 'relative';
            element.__resizeLast__ = {};
            element.__resizeListeners__ = [];
            (element.__resizeTriggers__ = document.createElement('div')).className = 'resize-triggers';
            element.__resizeTriggers__.innerHTML = '<div class="expand-trigger"><div></div></div>' +
                                                   '<div class="contract-trigger"></div>';
            element.appendChild(element.__resizeTriggers__);
            resetTriggers(element);
            element.addEventListener('scroll', scrollListener, true);
        }
        element.__resizeListeners__.push(fn);
    }
};

window.removeResizeListener = function(element, fn){
    if (attachEvent) element.detachEvent('resize', fn);
    else {
        element.__resizeListeners__.splice(element.__resizeListeners__.indexOf(fn), 1);
        if (!element.__resizeListeners__.length) {
            element.removeEventListener('scroll', scrollListener);
            element.__resizeTriggers__ = !element.removeChild(element.__resizeTriggers__);
        }
    }
}

})();

演示-licious!

这是该方法的伪代码用法.

var myElement = document.getElementById('my_element'),
    myResizeFn = function(){
        /* do something on resize */
    };
addResizeListener(myElement, myResizeFn);
removeResizeListener(myElement, myResizeFn);

Answer 3

我们现在有了ResizeObserver，今天（2021-01-21）浏览器支持率为 89.6%。

并且有针对旧浏览器的polyfill，例如juggle/resize-observer

Answer 4

只Window.onResize存在于规范.请记住,每个IFrame元素都会创建Window支持的新对象onResize.因此,IMO检测元素大小变化的最可靠方法是将隐藏的iframe附加到元素.

如果您对整洁便携的解决方案感兴趣,请检查此插件.它需要1行代码来监听更改div的宽度或高度的事件.

<!-- (1) include plugin script in a page -->
<script src="/src/jquery-element-onresize.js"></script>

// (2) use the detectResizing plugin to monitor changes to the element's size:
$monitoredElement.detectResizing({ onResize: monitoredElement_onResize });

// (3) write a function to react on changes:
function monitoredElement_onResize() {    
    // logic here...
}

Answer 5

一个纯粹且简单的 JavaScript 实现。

.resizable {
  resize: both;
  overflow: auto;
  width: 200px;
  border: 1px solid black;
  padding: 20px;
  margin-bottom: 120px;
}

<div class='resizable' onresize="this.innerText = this.w + ',' + this.h" onmousemove="if ((this.w && this.w !== this.offsetWidth) || (this.h && this.h !== this.offsetHeight)) { eval(this.getAttribute('onresize')) } this.w = this.offsetWidth; this.h = this.offsetHeight;">
test
</div>