JQuery learning notes 7 methods for building functions

1: $ (selectorStr [, restricted range]), accepts a selector (string conforming to jQuery specifications), and returns a jQuery object;

Copy codeThe Code is as follows:
// $ (Selector [, restricted range])
$ (". Guo"). click (function () {// There is no context parameter here
$ ("A. aguo", this).css ({"color": "red"}); // this is the context parameter, used to limit the range
});

Ii. $ (htmlStr [, Document Object]), $ (html [, json object]) is used to input an html string and create a new dom element.

When the input is a string, the constructor will determine whether it is a selector string or an html string .,
If a selector string is used, the dom is traversed to find the matched elements. If no matching element exists,
An empty jQuery object will be returned; otherwise, a jQuery object will be created for these matched elements.

Copy codeThe Code is as follows:
// $ (HtmlStr [, Document Object])
$ ("<Div> Hello everyone </div>"). append ("body"); // simple tag: no nodes

3. $ (dom element), $ (dom Element Set) converts dom elements to jQuery objects.

The jQuery constructor uses the original js method document. createElement () to create a dom node.

Copy codeThe Code is as follows:
$ ("<Div> <a> Hello everyone </a> </div>"). append ("body"); // complex Tag: Contains subnodes.

4. $ (custom object) encapsulates common objects as jQuery objects.

JQuery will use the document fragment buildFragment () method to insert all the child nodes to [, document Object] at a time. If this parameter is not specified, it will be document; $ (html [, json object])

When html is a simple tag, her second parameter can be a json object that contains the attributes or events of the dom element.

Copy codeThe Code is as follows:
// $ (Html [, json object])
$ ("<Div> </div> ",{
"Class": "gys", // because class is a js keyword, quotation marks are required.
Text: "Hello everyone ",
Click: function () {alert ("What Do I Do ");}
}). Append ("body ");

V. $ (callback function) bind the ready event listening function and execute it when the Dom load is complete.

$ (Element) or $ (elements)

Input a dom object or a set of dom objects

Copy codeThe Code is as follows:
("Div. guo"). click (function (){
$ (This). slideUp ();
});

Vi. $ (jQuery object) accepts a jQuery object and returns a copy of The jQuery object

$ (Object );

Input a Common Object

Copy codeThe Code is as follows:
Var obj = {name: "guo", age: 24 };
Var $ obj = $ (obj );
$ Obj. on ("guo", function (){
Alert ("starting a Custom Event ");
});
$ Obj. trigger ("guo ");

7: $ () creates an empty jQuery object.

$ (Callback) Incoming a function

Copy codeThe Code is as follows:
$ (Function (){})

This indicates that the function is executed after the Dom is loaded.

$ (JQuery Object );

When a jQuery object is input, a copy of the jQuery object is created and returned. The copy is identical to the referenced Dom object of the passed jQuery object.