Summary of several usage methods of setTimeout in jQuery

Let's use examples to illustrate several methods of setTimeout in jQuery. First, we have prepared the DIV and public functions used for testing:

Copy codeThe Code is as follows: <div id = "div_debug"> </div>
<Script src = "http://www.studyday.net/demo/jquery.js"> </script>
<Script language = "JavaScript">
Functionlog (s ){
$ ('# Div_debug'). append (s + '<br> ');
}

// The code for trial use in the following section can be placed under this line of comment, replace it //...
//...

</Script>

The basic usage of setTimeout in the original javascript is like this.

Copy codeThe Code is as follows: // basic setTimeout usage in original javascript
FunctionfunA (){
Log ('funa ...');
SetTimeout ('funa () ', 1000 );
}
FunA ();

The following are some usage methods of setTimeout in jQuery: Online instances.

Copy codeThe Code is as follows: // usage in jQuery
FunctionfunA (){
Log ('funa ...');
SetTimeout ('funa () ', 1000 );
}

JQuery (document). ready (function ($ ){
// Usage 1: Write the function to be called out of ready to make it a global function.
FunA ();

// Usage 2: Write the function name directly, without parentheses or quotation marks. This method is suitable for functions without parameters.
FunctionfunB (){
Log ('funb ...');
SetTimeout (funB, 1000 );
}
FunB ();

// Usage 3: it is suitable for functions with parameters to be executed by calling anonymous functions.
FunctionfunC (v ){
Log ('func... '+ v );
SetTimeout (function () {funC (v + 1)}, 1000 );
}
FunC (1 );

// Usage 4: by adding a function to the jQuery namespace, the application is wider.
$. Extend ({
FunD: function (v ){
Log ('Fund... '+ v );
SetTimeout ("$. funD (" + (v + 1) + ")", 1000 );
}
});
$. FunD (100 );
});

The difference between usage 2 and usage 3 is obvious, but what is the difference between usage 3 and usage 4? Why is usage 4 wider than usage 3? The following example shows the differences between the two:

Copy codeThe Code is as follows: jQuery (document). ready (function ($ ){
// Usage 3: it is suitable for functions with parameters to be executed by calling anonymous functions.
FunctionfunC (v ){
Log ('func... '+ v );
SetTimeout (function () {funC (v + 1)}, 1000 );
}

// Usage 4: It is easier to call by adding a function to the jQuery namespace
$. Extend ({
FunD: function (v ){
Log ('Fund... '+ v );
SetTimeout ("$. funD (" + (v + 1) + ")", 1000 );
}
});
});

JQuery (document). ready (function ($ ){
// FunC (1); // if this sentence is executed after the annotation is removed, an error is returned.
$. FunD (100); // This sentence is normal. Understand the difference between the two.
});