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How to understand the basis of javascript object-oriented technology, in view of this problem, this article introduces the corresponding analysis and solutions in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Function

Javascript function I believe you have written a lot, so we are only a brief introduction here.

Create a function:

Function f (x) {.}

Var f = function (x) {.}

The above two forms can create a function named f (), but the latter form can create an anonymous function. When defining the function, you can set parameters. If the number of parameters passed to the function is not enough, they correspond in turn from the leftmost. The rest are assigned with undefined. If the parameters passed to the function are more than the number of parameters defined by the function, the extra parameters are ignored.

Js code

Function myprint (S1 string2 s2) {alert (S1 + "_" + S2 + "_" + S3);} myprint (); / / undefined_undefined_undefined myprint ("string1", "string2"); / / string1_string2_undefined myprint ("string1", "string2", "string3", "string4"); / / string1_string2_string3

Therefore, for a defined function, we cannot expect the caller to pass in all the parameters. Parameters that must be used should be detected in the function body. Operator), or set the default value and operate with the parameter or (| |) to get the parameter.

Js code

Function myprint (S1 must be input person) {var defaultperson = {/ / default person object "name": "name1", "age": 18, "sex": "female"}; if (! S1) {/ / S1) {/ / S1 is not allowed to be empty alert ("S1 must be input!"); return false;} person = person | | defaultperson; / / accepts the person object parameter alert (S1 + "_" + person.name+ ":" + person.age+ ":" + person.sex) | Myprint (); / / S1 must be input! Myprint ("S1"); / / s1_name1:18:female myprint ("S1", {"name": "sdcyst", "age": 23, "sex": "male"}); / / s1_sdcyst:23:male

The arguments property of the function

Inside each function body, there is an arguments identifier, which represents an Arguments object. Arguments object is very similar to an Array (array) object, for example, both have a length property, and access its value using the index using the "[]" operator to access the parameter value, but the two are completely different and have only superficial commonalities (for example, modifying the length property of an Arguments object does not change its length).

Js code

Function myargs () {alert (arguments.length); alert (arguments [0]);} myargs (); / / 0-undefined myargs ("1", [1m 2]); / / 2-1

The Arguments object has a callee property that indicates the method in which the current Arguments object is located. You can use it to implement internal recursive calls to anonymous functions.

Js code

Function (x) {if (x)

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