How jquery determines whether a tag exists in an element

The method to determine whether a tag exists in an element in jquery: first obtain the element object; then use the "has('label object').length" method to determine whether a certain tag exists.

The operating environment of this article: Windows7 system, jquery1.2.6, Dell G3 computer.

jquery determines whether there is content or a certain tag in an element?

1. Determine whether the text is empty

var jqObj = $(this);
if(jqObj.text().trim()){ //trim()方法是去空格，$.trim()函数删除提供字符串的所有换行符,空格（包括非中断空格），开始和结束tab。如果这些空白字符在字符串中间发生时，它们将被保留。
jqObj.hide();
}

2. Determine whether there is a known element under this tag, such as determining whether there is a li element under the ul tag

var jqObj = $(this);
if(!jqObj.has('li').length){
jqObj.hide();
}

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