jquery sample code to determine whether the child elements of an element exist_jquery

jquery determines whether a child element exists

1. Determine whether the sub-element exists
//First-level sub-element if($("#specialId>img").length==0)
if ($( " #specialId:has(img)" ).length==0)                                                                                                                 
//-------There is an img sub-tag------
}


2. Select the specific id sub-element under the specific id element

$("#form" ).children( "#t" ) like this

3. Select the child element under a specific id element
$("ul#u> ;li:nth-child(2)" ) So

4. Determine whether an element exists
if ($( "#myId" ).length>0)
{
//Existence }