Custom User Selectors

In this chapter you will learn:

  1. How to create Custom User Selectors

Custom Selectors

You can extend the core jQuery object. The following code snippet creates a custom selector that selects elements with a red background.

<!DOCTYPE html> <!--from ja  v  a2 s  . c  o m-->
<html>
    <head>
        <script src="http://java2s.com/style/jquery-1.8.0.min.js"> 
        </script>
        <script>

            $(function(){ 
                $.expr[":"].redbg = function(element) {
                    return $(element).css("background-color") === "red"; 
                }; 
                var n = $(":redbg").length; 
                document.writeln(n);

            });
        </script> 
    </head> 
    <body>
        <div style="width:10; height:10; background-color:green;"></div> 
        <div style="width:10; height:10; background-color:red;"></div> 
        <div style="width:10; height:10; background-color:blue;"></div>

    </body> 
</html>

Click to view the demo

Next chapter...

What you will learn in the next chapter:

  1. How to escape characters
  2. How to escape the dot and []
Home » jQuery » jQuery Selector
Selector syntax
ID
Tag Name
Class Name
Descendant $('E F')
Child (E > F)
General sibling (E ~ F)
Multiple expressions (E, F, G)
Universal (*)
Filtering by Relationships
Numbered child (:nth-child(n/even/odd/expr))
First child (:first-child)
Last child (:last-child)
Only child (:only-child)
Not (:not(E))
Empty (:empty)
Attribute selectors
Attribute existence([attr])
Attribute equals ([foo=bar])
Attribute not equal ([foo!=bar])
Attribute begins with ([foo^=bar])
Attribute ends with ([foo$=bar])
Attribute contains ([foo*=bar])
Attribute contains word ([foo~=bar])
Attribute contains prefix ([foo|=bar])
Attribute exists $("[attributeName*='value']")
Form selector
Form input selector (:input)
Form text fields (input:text)
Form Password field (input:password)
Form Radio button (input:radio)
Form Checkbox (input:checkbox)
Form Submit button (input:submit)
Form Image button (input:image)
Form Reset button (input:reset)
Form button (input:button)
Form File upload (input:file)
Form Enabled form element (input:enabled)
Form Disabled form element (input:disabled)
Form Checked box (input:checked)
Form Selected option (input:selected)
Element at index (:eq(n))
Greater than (:gt(n))
Less than (:lt(n))
First (:first)
Last (:last)
Even element (:even)
Odd element (:odd)
parent (:parent)
Contains text (:contains(text))
Contains element (:has(E))
Visible (:visible)
Hidden (:hidden)
Header element (:header)
Currently animating (:animated)
$(this) selector
Custom User Selectors
Escape characters