JQuery get object simple implementation method summary

Monitor a container that pops up when the user clicks

The following code

$(function(){
$("Element").click{function(){
alert(" Click on me! ");
}
}
});

Basic object acquisition (note that these are Jquery objects and not Dom objects, but they can be converted)

The following code

$("*")  'means to get all objects   But I haven't used it yet 

$("#XXX") ' To obtain  id=XXX  Element object ( id It could be a label id or CSS style id )   The commonly used 

$("input[name='username']")  To obtain input In the label name='userName' Element object of   The commonly used 

$(".abc") '  Get the style class Is the name of .abc Element object of   The commonly used 

$("div") '  Label selector   Select all div The element   The commonly used 

$("#a,.b,span") ' Said to get ID is (www.jb51.net)a The element and USES the class style b And all of them span The element 

$("#a .b p") 'ID Number is a And used  b The style of   All of the p The element 

case

Suppose you have the following code.

var target_obj = jQuery('#target_obj_id');

Then, if you need to determine whether the id is target_obj_id, you can implement the following two methods:

1.

The following code

if (target_obj.length > 0) { //If greater than 0 identifies the existence of an object with an id of target_obj_id, otherwise there is no 



//Object existence processing logic 



} else {



//Object does not exist in the processing logic 



}

2,

The following code

if (target_obj[0]) {



//Object existence processing logic 



} else {



//Object does not exist in the processing logic 



}