The $() factory function:

All type of selectors available in jQuery, always start with the dollar sign and parentheses: $().

The factory function $() makes use of following three building blocks while selecting elements in a given document:

All the above items can be used either on their own or in combination with other selectors. All the jQuery selectors are based on the same principle except some tweaking.

NOTE: The factory function $() is a synonym of jQuery() function. So in case you are using any other JavaScript library where $ sign is conflicting with some thing else then you can replace $ sign by jQuery name and you can use function jQuery() instead of $().

Example:

Following is a simple example which makes use of Tag Selector. This would select all the elements with a tag name p.

   
   
   


   

      
This is a paragraph.

      
This is second paragraph.

      
This is third paragraph.

   

To understand it in better way you can Try it yourself.

How to use Selectors?

The selectors are very useful and would be required at every step while using jQuery. They get the exact element that you want from your HTML document.

Following table lists down few basic selectors and explains them with examples.

Similar to above syntax and examples, following examples would give you understanding on using different type of other useful selectors:

• $('*'): This selector selects all elements in the document.

• $("p > *"): This selector selects all elements that are children of a paragraph element.

• $("#specialID"): This selector function gets the element with id="specialID".

• $(".specialClass"): This selector gets all the elements that have the class of specialClass.

• $("li:not(.myclass)"): Selects all elements matched by

• that do not have class="myclass".

• $("a#specialID.specialClass"): This selector matches links with an id of specialID and a class of specialClass.

• $("p a.specialClass"): This selector matches links with a class of specialClass declared within

  elements.

• $("ul li:first"): This selector gets only the first

• element of the
  .

  • $("#container p"): Selects all elements matched by

    that are descendants of an element that has an id of container.

  • $("li > ul"): Selects all elements matched by

    that are children of an element matched by

    • $("strong + em"): Selects all elements matched by that immediately follow a sibling element matched by .

    • $("p ~ ul"): Selects all elements matched by

      that follow a sibling element matched by

      .

      • $("code, em, strong"): Selects all elements matched by or or .

      • $("p strong, .myclass"): Selects all elements matched by that are descendants of an element matched by

        as well as all elements that have a class of myclass.

      • $(":empty"): Selects all elements that have no children.

      • $("p:empty"): Selects all elements matched by

        that have no children.

      • $("div[p]"): Selects all elements matched by

        that contain an element matched by

        .

      • $("p[.myclass]"): Selects all elements matched by

        that contain an element with a class of myclass.

      • $("a[@rel]"): Selects all elements matched by that have a rel attribute.

      • $("input[@name=myname]"): Selects all elements matched by that have a name value exactly equal to myname.

      • $("input[@name^=myname]"): Selects all elements matched by that have a name value beginning with myname.

      • $("a[@rel$=self]"): Selects all elements matched by

        that have a class value ending with bar

      • $("a[@href*=domain.com]"): Selects all elements matched by that have an href value containing domain.com.

      • $("li:even"): Selects all elements matched by

      • that have an even index value.

      • $("tr:odd"): Selects all elements matched by that have an odd index value.

      • $("li:first"): Selects the first

      • element.

      • $("li:last"): Selects the last

      • element.

      • $("li:visible"): Selects all elements matched by

      • that are visible.

      • $("li:hidden"): Selects all elements matched by

      • that are hidden.

      • $(":radio"): Selects all radio buttons in the form.

      • $(":checked"): Selects all checked boxex in the form.

      • $(":input"): Selects only form elements (input, select, textarea, button).

      • $(":text"): Selects only text elements (input[type=text]).

      • $("li:eq(2)"): Selects the third

      • element

      • $("li:eq(4)"): Selects the fifth

      • element

      • $("li:lt(2)"): Selects all elements matched by

      • element before the third one; in other words, the first two
      • elements.

      • $("p:lt(3)"): selects all elements matched by

        elements before the fourth one; in other words the first three

        elements.

      • $("li:gt(1)"): Selects all elements matched by

      • after the second one.

      • $("p:gt(2)"): Selects all elements matched by

        after the third one.

      • $("div/p"): Selects all elements matched by

        that are children of an element matched by

        .

      • $("div//code"): Selects all elements matched by that are descendants of an element matched by

        .

      • $("//p//a"): Selects all elements matched by that are descendants of an element matched by

      • $("li:first-child"): Selects all elements matched by

      • that are the first child of their parent.

      • $("li:last-child"): Selects all elements matched by

      • that are the last child of their parent.

      • $(":parent"): Selects all elements that are the parent of another element, including text.

      • $("li:contains(second)"): Selects all elements matched by

      • that contain the text second.

      You can use all the above selectors with any HTML/XML element in generic way. For example if selector $("li:first") works for

    • element then $("p:first") would also work for

      element.

      
      Please refer the below link
      
      http://www.tutorialspoint.com/jquery/jquery-selectors.htm
      
      
      Thanks