有什么方法,我可以检查如果一个元素是可见的纯JS(没有jQuery) ?

因此,给定一个DOM元素,我如何检查它是否可见?我试着:

window.getComputedStyle(my_element)['display']);

但这似乎并不奏效。我想知道我应该检查哪些属性。我想到了:

display !== 'none'
visibility !== 'hidden'

还有我可能漏掉的吗?


当前回答

使用与jQuery相同的代码:

jQuery.expr.pseudos.visible = function( elem ) {
    return !!( elem.offsetWidth || elem.offsetHeight || elem.getClientRects().length );
};

在函数中:

function isVisible(e) {
    return !!( e.offsetWidth || e.offsetHeight || e.getClientRects().length );
}

在我的Win/IE10、Linux/Firefox中工作得很好。45岁的Linux / Chrome.52……

感谢没有jQuery的jQuery!

其他回答

如果你对用户可见感兴趣:

function isVisible(elem) {
    if (!(elem instanceof Element)) throw Error('DomUtil: elem is not an element.');
    const style = getComputedStyle(elem);
    if (style.display === 'none') return false;
    if (style.visibility !== 'visible') return false;
    if (style.opacity < 0.1) return false;
    if (elem.offsetWidth + elem.offsetHeight + elem.getBoundingClientRect().height +
        elem.getBoundingClientRect().width === 0) {
        return false;
    }
    const elemCenter   = {
        x: elem.getBoundingClientRect().left + elem.offsetWidth / 2,
        y: elem.getBoundingClientRect().top + elem.offsetHeight / 2
    };
    if (elemCenter.x < 0) return false;
    if (elemCenter.x > (document.documentElement.clientWidth || window.innerWidth)) return false;
    if (elemCenter.y < 0) return false;
    if (elemCenter.y > (document.documentElement.clientHeight || window.innerHeight)) return false;
    let pointContainer = document.elementFromPoint(elemCenter.x, elemCenter.y);
    do {
        if (pointContainer === elem) return true;
    } while (pointContainer = pointContainer.parentNode);
    return false;
}

测试对象(使用摩卡术语):

describe.only('visibility', function () {
    let div, visible, notVisible, inViewport, leftOfViewport, rightOfViewport, aboveViewport,
        belowViewport, notDisplayed, zeroOpacity, zIndex1, zIndex2;
    before(() => {
        div = document.createElement('div');
        document.querySelector('body').appendChild(div);
        div.appendChild(visible = document.createElement('div'));
        visible.style       = 'border: 1px solid black; margin: 5px; display: inline-block;';
        visible.textContent = 'visible';
        div.appendChild(inViewport = visible.cloneNode(false));
        inViewport.textContent = 'inViewport';
        div.appendChild(notDisplayed = visible.cloneNode(false));
        notDisplayed.style.display = 'none';
        notDisplayed.textContent   = 'notDisplayed';
        div.appendChild(notVisible = visible.cloneNode(false));
        notVisible.style.visibility = 'hidden';
        notVisible.textContent      = 'notVisible';
        div.appendChild(leftOfViewport = visible.cloneNode(false));
        leftOfViewport.style.position = 'absolute';
        leftOfViewport.style.right = '100000px';
        leftOfViewport.textContent = 'leftOfViewport';
        div.appendChild(rightOfViewport = leftOfViewport.cloneNode(false));
        rightOfViewport.style.right       = '0';
        rightOfViewport.style.left       = '100000px';
        rightOfViewport.textContent = 'rightOfViewport';
        div.appendChild(aboveViewport = leftOfViewport.cloneNode(false));
        aboveViewport.style.right       = '0';
        aboveViewport.style.bottom       = '100000px';
        aboveViewport.textContent = 'aboveViewport';
        div.appendChild(belowViewport = leftOfViewport.cloneNode(false));
        belowViewport.style.right       = '0';
        belowViewport.style.top       = '100000px';
        belowViewport.textContent = 'belowViewport';
        div.appendChild(zeroOpacity = visible.cloneNode(false));
        zeroOpacity.textContent   = 'zeroOpacity';
        zeroOpacity.style.opacity = '0';
        div.appendChild(zIndex1 = visible.cloneNode(false));
        zIndex1.textContent = 'zIndex1';
        zIndex1.style.position = 'absolute';
        zIndex1.style.left = zIndex1.style.top = zIndex1.style.width = zIndex1.style.height = '100px';
        zIndex1.style.zIndex = '1';
        div.appendChild(zIndex2 = zIndex1.cloneNode(false));
        zIndex2.textContent = 'zIndex2';
        zIndex2.style.left = zIndex2.style.top = '90px';
        zIndex2.style.width = zIndex2.style.height = '120px';
        zIndex2.style.backgroundColor = 'red';
        zIndex2.style.zIndex = '2';
    });
    after(() => {
        div.parentNode.removeChild(div);
    });
    it('isVisible = true', () => {
        expect(isVisible(div)).to.be.true;
        expect(isVisible(visible)).to.be.true;
        expect(isVisible(inViewport)).to.be.true;
        expect(isVisible(zIndex2)).to.be.true;
    });
    it('isVisible = false', () => {
        expect(isVisible(notDisplayed)).to.be.false;
        expect(isVisible(notVisible)).to.be.false;
        expect(isVisible(document.createElement('div'))).to.be.false;
        expect(isVisible(zIndex1)).to.be.false;
        expect(isVisible(zeroOpacity)).to.be.false;
        expect(isVisible(leftOfViewport)).to.be.false;
        expect(isVisible(rightOfViewport)).to.be.false;
        expect(isVisible(aboveViewport)).to.be.false;
        expect(isVisible(belowViewport)).to.be.false;
    });
});

使用与jQuery相同的代码:

jQuery.expr.pseudos.visible = function( elem ) {
    return !!( elem.offsetWidth || elem.offsetHeight || elem.getClientRects().length );
};

在函数中:

function isVisible(e) {
    return !!( e.offsetWidth || e.offsetHeight || e.getClientRects().length );
}

在我的Win/IE10、Linux/Firefox中工作得很好。45岁的Linux / Chrome.52……

感谢没有jQuery的jQuery!

这是一种确定所有css属性(包括可见性)的方法:

html:

<div id="element">div content</div>

css:

#element
{
visibility:hidden;
}

javascript:

var element = document.getElementById('element');
 if(element.style.visibility == 'hidden'){
alert('hidden');
}
else
{
alert('visible');
}

它适用于任何css属性,非常通用和可靠。

来自http://code.jquery.com/jquery-1.11.1.js的jQuery代码有一个isHidden参数

var isHidden = function( elem, el ) {
    // isHidden might be called from jQuery#filter function;
    // in that case, element will be second argument
    elem = el || elem;
    return jQuery.css( elem, "display" ) === "none" || !jQuery.contains( elem.ownerDocument, elem );
};

因此,看起来有一个与所有者文档相关的额外检查

我想知道这是否真的适用于以下情况:

基于zIndex隐藏在其他元素后面的元素 完全透明的元素使它们不可见 位于屏幕外的元素(即左:-1000px) 具有可见性的元素:隐藏 有显示的元素:无 没有可见文本或子元素的元素 高度或宽度设置为0的元素

这可能会有帮助: 将元素隐藏在最左边的位置,然后检查offsetLeft属性。如果你想使用jQuery,你可以简单地检查:visible选择器并获得元素的可见状态。

HTML:

<div id="myDiv">Hello</div>

CSS:

<!-- for javaScript-->
#myDiv{
   position:absolute;
   left : -2000px;
}

<!-- for jQuery -->
#myDiv{
    visibility:hidden;
}

javaScript:

var myStyle = document.getElementById("myDiv").offsetLeft;

if(myStyle < 0){
     alert("Div is hidden!!");
}

jQuery:

if(  $("#MyElement").is(":visible") == true )
{  
     alert("Div is visible!!");        
}

js小提琴