jquery determines whether element content exists

This time I will bring you jquery to determine whether the element content exists. What are the precautions for jquery to determine whether the element content exists? The following is a practical case, let's take a look.

Input uses val();

var value = $('#test').val();

Judge whether it is empty Method:

if(value.length == 0){} Operations performed if value is empty

if(value!=''){} Operations performed if value is not null

jQuery verifies that the content of the text box is not empty

Extended jQuery method through $.fn

/**
 * 校验文本是否为空
 * tips：提示信息
 * 使用方法：$("#id").validate("提示文本");
 * @itmyhome
 */
$.fn.validate = function(tips){
  if($(this).val() == "" || $.trim($(this).val()).length == 0){
    alert(tips + "不能为空！");
    throw SyntaxError(); //如果验证不通过，则不执行后面
  }
}

html elementUse html();

var value = $('#test').html();

How to judge whether it is empty:

if (value.length == 0){

You can also judge whether there are any child nodes? For the method of html acquisition,

$('#list').children().length === 0 is available.

Method 1

<script></script>
<p></p>

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<script> alert($(&#39;#thelist2&#39;).children().length) alert($(&#39;#thelist3&#39;).children().length) $thelist3 = $(&#39;#thelist3&#39;); if($thelist3.children().length==0){ //插入广告 } /* thel3con = $(&#39;#thelist3&#39;).html(); alert(thel3con.length); if(thel3con=""){ alert("空"); }else{ alert("非空"); } */ </script>Method 2,

String.prototype.isEmpty = function () {
 var s1 = this.replace(/[\r\n]/g, '').replace(/[ ]/g, ''),
   s2 = (s1 == '') ? true : false;
 return s2;
};
$list.html().isEmpty();

if( $("#list").html() === "" ){} Use three etc. The number is more in line with

. I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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