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我如何检查,如果元素是隐藏在jQuery?

It is possible to toggle the visibility of an element, using the functions .hide(), .show() or .toggle().

How would you test if an element is visible or hidden?


Since the question refers to a single element, this code might be more suitable:

// Checks for display:[none|block], ignores visible:[true|false]
$(element).is(":visible"); 

Same as twernt's suggestion, but applied to a single element; and it matches the algorithm recommended in the jQuery FAQ

2018年02月24日58分42秒

You can use the hidden selector:

// Matches all elements that are hidden
$('element:hidden')

And the visible selector:

// Matches all elements that are visible
$('element:visible')

2018年02月24日58分42秒

if ( $(element).css('display') == 'none' ){
    // element is hidden
}

Functions don't work with the visibility attribute.

2018年02月24日58分42秒

None of these answers address what I understand to be the question, which is what I was searching for, "How do I handle items that have visibility: hidden?". Neither :visible nor :hidden will handle this, as they are both looking for display per the documentation. As far as I could determine, there is no selector to handle CSS visibility. Here is how I resolved it (standard jQuery selectors, there may be a more condensed syntax):

$(".item").each(function() {
    if ($(this).css("visibility") == "hidden") {
        // handle non visible state
    } else {
        // handle visible state
    }
});

2018年02月24日58分42秒

From How do I determine the state of a toggled element?


You can determine whether an element is collapsed or not by using the :visible and :hidden selectors.

var isVisible = $('#myDiv').is(':visible');
var isHidden = $('#myDiv').is(':hidden');

If you're simply acting on an element based on its visibility, you can just include :visible or :hidden in the selector expression. For example:

 $('#myDiv:visible').animate({left: '+=200px'}, 'slow');

2018年02月24日58分42秒

Often when checking if something is visible or not, you are going to go right ahead immediately and do something else with it. jQuery chaining makes this easy.

So if you have a selector and you want to perform some action on it only if is visible or hidden, you can use filter(":visible") or filter(":hidden") followed by chaining it with the action you want to take.

So instead of an if statement, like this:

if ($('#btnUpdate').is(":visible"))
{
     $('#btnUpdate').animate({ width: "toggle" });   // Hide button
}

Or more efficient, but even uglier:

var button = $('#btnUpdate');
if (button.is(":visible"))
{
     button.animate({ width: "toggle" });   // Hide button
}

You can do it all in one line:

$('#btnUpdate').filter(":visible").animate({ width: "toggle" });

2018年02月24日58分42秒

The :visible selector according to the jQuery documentation:

  • They have a CSS display value of none.
  • They are form elements with type="hidden".
  • Their width and height are explicitly set to 0.
  • An ancestor element is hidden, so the element is not shown on the page.

Elements with visibility: hidden or opacity: 0 are considered to be visible, since they still consume space in the layout.

This is useful in some cases and useless in others, because if you want to check if the element is visible (display != none), ignoring the parents visibility, you will find that doing .css("display") == 'none' is not only faster, but will also return the visibility check correctly.

If you want to check visibility instead of display, you should use: .css("visibility") == "hidden".

Also take into consideration the additional jQuery notes:

Because :visible is a jQuery extension and not part of the CSS specification, queries using :visible cannot take advantage of the performance boost provided by the native DOM querySelectorAll() method. To achieve the best performance when using :visible to select elements, first select the elements using a pure CSS selector, then use .filter(":visible").

Also, if you are concerned about performance, you should check Now you see me… show/hide performance (2010-05-04). And use other methods to show and hide elements.

2018年02月24日58分42秒

This works for me, and I am using show() and hide() to make my div hidden/visible:

if( $(this).css('display') == 'none' ){
    /* your code goes here */
} else {
    /* alternate logic   */
}

2018年02月24日58分42秒

How element visibility and jQuery works;

An element could be hidden with display:none, visibility:hidden or opacity:0. The difference between those methods:

  • display:none hides the element, and it does not take up any space;
  • visibility:hidden hides the element, but it still takes up space in the layout;
  • opacity:0 hides the element as "visibility:hidden", and it still takes up space in the layout; the only difference is that opacity lets one to make an element partly transparent;

    if ($('.target').is(':hidden')) {
      $('.target').show();
    } else {
      $('.target').hide();
    }
    if ($('.target').is(':visible')) {
      $('.target').hide();
    } else {
      $('.target').show();
    }
    
    if ($('.target-visibility').css('visibility') == 'hidden') {
      $('.target-visibility').css({
        visibility: "visible",
        display: ""
      });
    } else {
      $('.target-visibility').css({
        visibility: "hidden",
        display: ""
      });
    }
    
    if ($('.target-visibility').css('opacity') == "0") {
      $('.target-visibility').css({
        opacity: "1",
        display: ""
      });
    } else {
      $('.target-visibility').css({
        opacity: "0",
        display: ""
      });
    }
    

    Useful jQuery toggle methods:

    $('.click').click(function() {
      $('.target').toggle();
    });
    
    $('.click').click(function() {
      $('.target').slideToggle();
    });
    
    $('.click').click(function() {
      $('.target').fadeToggle();
    });
    

2018年02月24日58分42秒

I would use CSS class .hide { display: none!important; }.

For hiding/showing, I call .addClass("hide")/.removeClass("hide"). For checking visibility, I use .hasClass("hide").

It's a simple and clear way to check/hide/show elements, if you don't plan to use .toggle() or .animate() methods.

2018年02月24日58分42秒

You can also do this using plain JavaScript:

function isRendered(domObj) {
    if ((domObj.nodeType != 1) || (domObj == document.body)) {
        return true;
    }
    if (domObj.currentStyle && domObj.currentStyle["display"] != "none" && domObj.currentStyle["visibility"] != "hidden") {
        return isRendered(domObj.parentNode);
    } else if (window.getComputedStyle) {
        var cs = document.defaultView.getComputedStyle(domObj, null);
        if (cs.getPropertyValue("display") != "none" && cs.getPropertyValue("visibility") != "hidden") {
            return isRendered(domObj.parentNode);
        }
    }
    return false;
}

Notes:

  1. Works everywhere

  2. Works for nested elements

  3. Works for CSS and inline styles

  4. Doesn't require a framework

2018年02月24日58分42秒

One can simply use the hidden or visible attribute, like:

$('element:hidden')
$('element:visible')

Or you can simplify the same with is as follows.

$(element).is(":visible")

2018年02月24日58分42秒

Another answer you should put into consideration is if you are hiding an element, you should use jQuery, but instead of actually hiding it, you remove the whole element, but you copy its HTML content and the tag itself into a jQuery variable, and then all you need to do is test if there is such a tag on the screen, using the normal if (!$('#thetagname').length).

2018年02月24日58分42秒

ebdiv should be set to style="display:none;". It is works for show and hide:

$(document).ready(function(){
    $("#eb").click(function(){
        $("#ebdiv").toggle();
    });    
});

2018年02月24日58分42秒

$('#clickme').click(function() {
  $('#book').toggle('slow', function() {
    // Animation complete.
    alert($('#book').is(":visible")); //<--- TRUE if Visible False if Hidden
  });
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="clickme">
  Click here
</div>
<img id="book" src="http://www.chromefusion.com/wp-content/uploads/2012/06/chrome-logo.jpg" alt="" />

Source:

Blogger Plug n Play - jQuery Tools and Widgets: How to See if Element is hidden or Visible Using jQuery

jsFiddle:

JSFiddle - ipsjolly - k4WWj

2018年02月24日58分42秒

When testing an element against :hidden selector in jQuery it should be considered that an absolute positioned element may be recognized as hidden although their child elements are visible.

This seems somewhat counter-intuitive in the first place – though having a closer look at the jQuery documentation gives the relevant information:

Elements can be considered hidden for several reasons: [...] Their width and height are explicitly set to 0. [...]

So this actually makes sense in regards to the box-model and the computed style for the element. Even if width and height are not set explicitly to 0 they may be set implicitly.

Have a look at the following example:

console.log($('.foo').is(':hidden')); // true
console.log($('.bar').is(':hidden')); // false
.foo {
  position: absolute;
  left: 10px;
  top: 10px;
  background: #ff0000;
}

.bar {
  position: absolute;
  left: 10px;
  top: 10px;
  width: 20px;
  height: 20px;
  background: #0000ff;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="foo">
  <div class="bar"></div>
</div>


UPDATE FOR JQUERY 3.x:

With jQuery 3 the described behavior will change! Elements will be considered visible if they have any layout boxes, including those of zero width and/or height.

JSFiddle with jQuery 3.0.0-alpha1:

http://jsfiddle.net/pM2q3/7/

The same JS will then have this output:

console.log($('.foo').is(':hidden')); // false
console.log($('.bar').is(':hidden')); // false

2018年02月24日58分42秒

This may work:

expect($("#message_div").css("display")).toBe("none");

2018年02月24日58分42秒

To check if it is not visible I use !:

if ( !$('#book').is(':visible')) {
    alert('#book is not visible')
}

Or the following is also the sam, saving the jQuery selector in a variable to have better performance when you need it multiple times:

var $book = $('#book')

if(!$book.is(':visible')) {
    alert('#book is not visible')
}

2018年02月24日58分42秒

Example:

$(document).ready(function() {
  if ($("#checkme:hidden").length) {
    console.log('Hidden');
  }
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="checkme" class="product" style="display:none">
  <span class="itemlist"><!-- Shows Results for Fish --></span> Category:Fish
  <br>Product: Salmon Atlantic
  <br>Specie: Salmo salar
  <br>Form: Steaks
</div>

2018年02月24日58分42秒

Use class toggling, not style editing . . .

Using classes designated for "hiding" elements is easy and also one of the most efficient methods. Toggling a class 'hidden' with a Display style of 'none' will perform faster than editing that style directly. I explained some of this pretty thoroughly in Stack Overflow question Turning two elements visible/hidden in the same div.


JavaScript Best Practices and Optimization

Here is a truly enlightening video of a Google Tech Talk by Google front-end engineer Nicholas Zakas:

2018年02月24日58分42秒

Example of using the visible check for adblocker is activated:

$(document).ready(function(){
  if(!$("#ablockercheck").is(":visible"))
    $("#ablockermsg").text("Please disable adblocker.").show();
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="ad-placement" id="ablockercheck"></div>
<div id="ablockermsg" style="display: none"></div>

"ablockercheck" is a ID which adblocker blocks. So checking it if it is visible you are able to detect if adblocker is turned On.

2018年02月24日58分42秒

After all, none of examples suits me, so I wrote my own.

Tests (no support of Internet Explorer filter:alpha):

a) Check if the document is not hidden

b) Check if an element has zero width / height / opacity or display:none / visibility:hidden in inline styles

c) Check if the center (also because it is faster than testing every pixel / corner) of element is not hidden by other element (and all ancestors, example: overflow:hidden / scroll / one element over enother) or screen edges

d) Check if an element has zero width / height / opacity or display:none / visibility:hidden in computed styles (among all ancestors)

Tested on

Android 4.4 (Native browser/Chrome/Firefox), Firefox (Windows/Mac), Chrome (Windows/Mac), Opera (Windows Presto/Mac Webkit), Internet Explorer (Internet Explorer 5-11 document modes + Internet Explorer 8 on a virtual machine), Safari (Windows/Mac/iOS)

var is_visible = (function () {
    var x = window.pageXOffset ? window.pageXOffset + window.innerWidth - 1 : 0,
        y = window.pageYOffset ? window.pageYOffset + window.innerHeight - 1 : 0,
        relative = !!((!x && !y) || !document.elementFromPoint(x, y));
        function inside(child, parent) {
            while(child){
                if (child === parent) return true;
                child = child.parentNode;
            }
        return false;
    };
    return function (elem) {
        if (
            document.hidden ||
            elem.offsetWidth==0 ||
            elem.offsetHeight==0 ||
            elem.style.visibility=='hidden' ||
            elem.style.display=='none' ||
            elem.style.opacity===0
        ) return false;
        var rect = elem.getBoundingClientRect();
        if (relative) {
            if (!inside(document.elementFromPoint(rect.left + elem.offsetWidth/2, rect.top + elem.offsetHeight/2),elem)) return false;
        } else if (
            !inside(document.elementFromPoint(rect.left + elem.offsetWidth/2 + window.pageXOffset, rect.top + elem.offsetHeight/2 + window.pageYOffset), elem) ||
            (
                rect.top + elem.offsetHeight/2 < 0 ||
                rect.left + elem.offsetWidth/2 < 0 ||
                rect.bottom - elem.offsetHeight/2 > (window.innerHeight || document.documentElement.clientHeight) ||
                rect.right - elem.offsetWidth/2 > (window.innerWidth || document.documentElement.clientWidth)
            )
        ) return false;
        if (window.getComputedStyle || elem.currentStyle) {
            var el = elem,
                comp = null;
            while (el) {
                if (el === document) {break;} else if(!el.parentNode) return false;
                comp = window.getComputedStyle ? window.getComputedStyle(el, null) : el.currentStyle;
                if (comp && (comp.visibility=='hidden' || comp.display == 'none' || (typeof comp.opacity !=='undefined' && comp.opacity != 1))) return false;
                el = el.parentNode;
            }
        }
        return true;
    }
})();

How to use:

is_visible(elem) // boolean

2018年02月24日58分42秒

You need to check both... Display as well as visibility:

if ($(this).css("display") == "none" || $(this).css("visibility") == "hidden") {
    // The element is not visible
} else {
    // The element is visible
}

If we check for $(this).is(":visible"), jQuery checks for both the things automatically.

2018年02月24日58分42秒

Maybe you can do something like this

$(document).ready(function() {
   var visible = $('#tElement').is(':visible');

   if(visible) {
      alert("visible");
                    // Code
   }
   else
   {
      alert("hidden");
   }
});
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>

<input type="text" id="tElement" style="display:block;">Firstname</input>

2018年02月24日58分42秒

Because Elements with visibility: hidden or opacity: 0 are considered visible, since they still consume space in the layout (as described for jQuery :visible Selector) - we can check if element is really visible in this way:

function isElementReallyHidden (el) {
    return $(el).is(":hidden") || $(el).css("visibility") == "hidden" || $(el).css('opacity') == 0;
}

var booElementReallyShowed = !isElementReallyHidden(someEl);
$(someEl).parents().each(function () {
    if (isElementReallyHidden(this)) {
        booElementReallyShowed = false;
    }
});

2018年02月24日58分42秒

if($('#postcode_div').is(':visible')) {
    if($('#postcode_text').val()=='') {
        $('#spanPost').text('\u00a0');
    } else {
        $('#spanPost').text($('#postcode_text').val());
}

2018年02月24日58分42秒

But what if the element's CSS is like the following?

.element{
    position: absolute;left:-9999;    
}

So this answer to Stack Overflow question How to check if an element is off-screen should also be considered.

2018年02月24日58分42秒

A function can be created in order to check for visibility/display attributes in order to gauge whether the element is shown in the UI or not.

function checkUIElementVisible(element) {
    return ((element.css('display') !== 'none') && (element.css('visibility') !== 'hidden'));
}

Working Fiddle

2018年02月24日58分42秒

Simply check visibility by checking for a boolean value, like:

if (this.hidden === false) {
    // Your code
}

I used this code for each function. Otherwise you can use is(':visible') for checking the visibility of an element.

2018年02月24日58分42秒

Also here's a ternary conditional expression to check the state of the element and then to toggle it:

$('someElement').on('click', function(){ $('elementToToggle').is(':visible') ? $('elementToToggle').hide('slow') : $('elementToToggle').show('slow'); });

2018年02月24日58分42秒