Summary of JavaScript functions

JavaScript functions are a class-one citizen, functions can exist alone, regardless of function definition within that function, can be called by other objects

For example:

function person (name)

{

var walk = function ()

{

Alert ("I'll Run");

}

}

Walk.call (window);

Although the walk function is a person, the function can be called by another object.

Methods for defining functions

The first type:

functoion function Name (P1, p2)

{

function execution Body;

return p1 + p2;

}

The second type//use more

var tt = fuction (P1, p2)

{

return p1 + p2;

}

Third Kind

New function (P1,P2, P3......PN)

{

PN is the executing body;

}

Focus: Each time you define a JS function, you produce one class at a time.

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Use the difference without using Var:

→ If you use var to define a variable, the program will force a new variable to be defined.

→ If a variable is not defined using VAR, the system will first search for the variable in the current context, and the system will redefine a new variable only if the variable does not exist.

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JavaScript is not overloaded with methods, it is according to the latest definition of the method

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function call;

Call directly:

P.walk ();

Invoke the function with the call () method;

Function name. Call (caller, parameter 1, parameter 2 ...);

The caller. function (parameter 1, parameter 2, ...) = functions name. Call (caller, parameter 1, parameter 2 ...)

Call with the Apply () method

Name of the function. Apply (caller, arguments)

For example myfun.apply (window, [12, 3, 4]);

Summary of JavaScript functions