I just want to know how to call a javascript function inside another function. If I have the code below, how do I call the second function inside the first?
function function_one[]
{
alert["The function called 'function_one' has been called."]
//Here I would like to call function_two.
}
function function_two[]
{
alert["The function called 'function_two' has been called."]
}
SandPiper
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asked Dec 24, 2010 at 7:26
Web_DesignerWeb_Designer
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function function_one[] {
function_two[]; // considering the next alert, I figured you wanted to call function_two first
alert["The function called 'function_one' has been called."];
}
function function_two[] {
alert["The function called 'function_two' has been called."];
}
function_one[];
A little bit more context: this works in JavaScript because of a language feature called "variable hoisting" - basically, think of it like variable/function declarations are put at the top of the scope [more info].
answered Dec 24, 2010 at 7:28
ChristianChristian
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2
function function_one[] {
function_two[];
}
function function_two[] {
//enter code here
}
Diganta
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answered Nov 13, 2012 at 11:25
0
function function_one[]
{
alert["The function called 'function_one' has been called."]
//Here u would like to call function_two.
function_two[];
}
function function_two[]
{
alert["The function called 'function_two' has been called."]
}
Icarus
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answered Aug 24, 2016 at 13:09
function function_first[] {
function_last[];
alert["The function called 'function_first' has been called."];
}
function function_last[] {
alert["The function called 'function_last' has been called."];
}
function_first[];
answered Nov 30, 2021 at 12:01
Method Reuse
With the call[]
method, you can write a method that can be used on different objects.
All Functions are Methods
In JavaScript all functions are object methods.
If a function is not a method of a JavaScript object, it is a function of the global object [see previous chapter].
The example below creates an object with 3 properties, firstName, lastName, fullName.
Example
const person = {
firstName:"John",
lastName: "Doe",
fullName: function [] {
return this.firstName + " " + this.lastName;
}
}
// This will return "John Doe":
person.fullName[];
Try it Yourself »
In the example above, this
refers to the person object.
this.firstName means the firstName property of this.
Same as:
this.firstName means the firstName property of person.
What is this?
In JavaScript, the this
keyword refers to an object.
Which object depends on how this
is being invoked [used or called].
The this
keyword refers to different objects depending on how it is used:
In an object method, this refers to the object.
|
Alone, this refers to the global object.
|
In a function, this refers to the global object.
|
In a function, in strict mode, this is undefined .
|
In an event, this refers to the element that received the event.
|
Methods like call[] , apply[] , and bind[] can refer this to any object.
|
The JavaScript call[] Method
The call[]
method is a predefined JavaScript method.
It can be used to invoke [call] a method with an owner object as an argument [parameter].
With call[]
, an object can use a method belonging to another object.
This example calls the fullName method of person, using it on person1:
Example
const person = {
fullName:
function[] {
return this.firstName + " " + this.lastName;
}
}
const person1 = {
firstName:"John",
lastName: "Doe"
}
const person2 = {
firstName:"Mary",
lastName: "Doe"
}
// This will return "John Doe":
person.fullName.call[person1];
Try it Yourself »
This example calls the fullName method of person, using it on person2:
Example
const person = {
fullName: function[] {
return this.firstName + " " + this.lastName;
}
}
const person1 = {
firstName:"John",
lastName: "Doe"
}
const person2 = {
firstName:"Mary",
lastName: "Doe"
}
//
This will return "Mary Doe"
person.fullName.call[person2];
Try it Yourself »
The call[] Method with Arguments
The call[]
method can accept arguments:
Example
const person = {
fullName: function[city, country] {
return this.firstName + " " + this.lastName + "," + city + "," +
country;
}
}
const person1 = {
firstName:"John",
lastName: "Doe"
}
person.fullName.call[person1, "Oslo", "Norway"];
Try it Yourself »