如何使用jQuery检查HTML元素是否为空？

Question

I'm trying to call a function only if an HTML element is empty, using jQuery.

Something like this:

if (isEmpty($('#element'))) {
    // do something
}

Answer 1

if ($('#element').is(':empty')){
  //do something
}

for more info see http://api.jquery.com/is/ and http://api.jquery.com/empty-selector/

EDIT:

As some have pointed, the browser interpretation of an empty element can vary. If you would like to ignore invisible elements such as spaces and line breaks and make the implementation more consistent you can create a function (or just use the code inside of it).

  function isEmpty( el ){
      return !$.trim(el.html())
  }
  if (isEmpty($('#element'))) {
      // do something
  }

You can also make it into a jQuery plugin, but you get the idea.

Answer 2

我发现这是唯一可靠的方法（因为Chrome和FF将空格和换行符视为元素）：

if($.trim($("selector").html())=='')

Answer 3

White space and line breaks are the main issues with using :empty selector. Careful, in CSS the :empty pseudo class behaves the same way. I like this method:

if ($someElement.children().length == 0){
     someAction();
}

Answer 4

!elt.hasChildNodes()

Yes, I know, this is not jQuery, so you could use this:

!$(elt)[0].hasChildNodes()

Happy now?

Answer 5

jQuery.fn.doSomething = function() {
   //return something with 'this'
};

$('selector:empty').doSomething();

Answer 6

If by "empty", you mean with no HTML content,

if($('#element').html() == "") {
  //call function
}

Answer 7

Empty as in contains no text?

if (!$('#element').text().length) {
    ...
}

Answer 8

In resume, there are many options to find out if an element is empty:

1- Using html :

if (!$.trim($('p#element').html())) {
    // paragraph with id="element" is empty, your code goes here
}

2- Using text :

if (!$.trim($('p#element').text())) {
    // paragraph with id="element" is empty, your code goes here
}

3- Using is(':empty') :

if ($('p#element').is(':empty')) {
    // paragraph with id="element" is empty, your code goes here
}

4- Using length

if (!$('p#element').length){
    // paragraph with id="element" is empty, your code goes here
}

In addiction if you are trying to find out if an input element is empty you can use val :

if (!$.trim($('input#element').val())) {
    // input with id="element" is empty, your code goes here
}

Answer 9

Another option that should require less "work" for the browser than html() or children() :

function isEmpty( el ){
  return !el.has('*').length;
}

Answer 10

document.getElementById("id").innerHTML == "" || null

要么

$("element").html() == "" || null

Answer 11

You can try:

if($('selector').html().toString().replace(/ /g,'') == "") {
//code here
}

*Replace white spaces, just incase ;)

Answer 12

Are you looking for jQuery.isEmptyObject() ?

http://api.jquery.com/jquery.isemptyobject/

Answer 13

Here's a jQuery filter based on https://stackoverflow.com/a/6813294/698289

$.extend($.expr[':'], {
  trimmedEmpty: function(el) {
    return !$.trim($(el).html());
  }
});

Answer 14

JavaScript

var el= document.querySelector('body'); 
console.log(el);
console.log('Empty : '+ isEmptyTag(el));
console.log('Having Children : '+ hasChildren(el));


function isEmptyTag(tag) { 
    return (tag.innerHTML.trim() === '') ? true : false ;
}
function hasChildren(tag) {
    //return (tag.childElementCount !== 0) ? true : false ; // Not For IE
    //return (tag.childNodes.length !== 0) ? true : false ; // Including Comments
    return (tag.children.length !== 0) ? true : false ; // Only Elements
}

try using any of this!

document.getElementsByTagName('div')[0];
document.getElementsByClassName('topbar')[0];

document.querySelectorAll('div')[0];
document.querySelector('div'); // gets the first element.
​

Answer 15

Try this:

if (!$('#el').html()) {
    ...
}

Answer 16

if($("#element").html() === "")
{

}

Answer 17

Line breaks are considered as content to elements in FF.

<div>
</div>
<div></div>

Ex:

$("div:empty").text("Empty").css('background', '#ff0000');

In IE both divs are considered empty, in FF an Chrome only the last one is empty.

You can use the solution provided by @qwertymk

if(!/[\S]/.test($('#element').html())) { // for one element
    alert('empty');
}

or

$('.elements').each(function(){  // for many elements
    if(!/[\S]/.test($(this).html())) { 
        // is empty
    }
})