How to access variable inside another function

Question

I have a function to calculate the screen width

var screenWidth = jQuery(window).width();

function checkScreenSize()
{   
    screenWidth = jQuery(window).width();
}

jQuery(window).on("resize", checkScreenSize).resize();

How can I use this screenWidth inside another function?

EDIT:

I want to access this variable here, for example:

function showContent() {
    if(screenWidth <= 1000)
    {
         console.log(screenWidth);
    }
}

I think what @Deep wanted to know is, where do you define this function at where do you call it. If it is called before the checkScreenSize Method has completed then, the variable has not been set with the width value. Do you call it every time a resize event happens? How do you synchronize the two methods? If schowContent is defined outside of the scope where the var screenWith variable (which is not nessecarily a "global" variable; you could have defined it in another function body or in a requirejs module) is defined then, the screenWith will be unknown to the showContent Method. — Peter Paul Kiefer
– Peter Paul Kiefer, Commented Jan 8, 2017 at 11:44

Lajos Arpad · Accepted Answer · 2017-01-08 11:13:08Z

1

Since screenWidth is a global variable declared outside the function you have mentioned, you can access it as it is:

function foo() {
    console.log(screenWidth);
}

answered Jan 8, 2017 at 11:13

Lajos Arpad

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2 Comments

Keith Over a year ago

I should have said that I need the screen width to update when the window is size also

Lajos Arpad Over a year ago

@KeithDonegan your global variable is accessible from anywhere. If you need to update it on different actions, then you need to add handlers for that purpose. You already have a resize handler. How is this not working and what do you want to achieve instead?

maioman · Accepted Answer · 2017-01-08 11:15:45Z

0

Your global screenWidthis quite useless...

if you need to know the width inside the resize handler callback that's where you need to call jQuery(window).width()

function checkScreenSize(){
  var w = $(window).width()
  console.log(w)
}

jQuery(window).on("resize", checkScreenSize)

// .resize() is a shorthand for .on('resize' method

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

answered Jan 8, 2017 at 11:15

maioman

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Comments

Komeil Tl · Accepted Answer · 2017-01-08 11:16:35Z

0

when you defined variable out of function , it will be global variable and you can use it in other function !!
do you have problme with this ?

you can also visit : http://www.w3schools.com/js/js_scope.asp

answered Jan 8, 2017 at 11:16

Komeil Tl

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Comments

score 0 · Accepted Answer · 2017-01-08 11:32:08Z

0

You can achieve this by defining said variable in global scope; if that var screenWidth = ... is defined inside some other function context you will not have access to it from other functions.

Using globals is a bad idea; however, in many cases you need some variable value that you need access to from other places. In this case, you could construct a well defined "Globals" container, like i.e:

'use strict';        // strict mode    :: prevents nasty bugs
this.Main = this;    // super-global   :: refers `window` -or- `global`

Main.Globals = {screenWidth:null};

// your dynamic screen resizing code here sets the `Globals.screenWidth`
// now you have access to this anywhere

You can also write some code to have this Globals object be only writable by certain functions, but this technique is probably out of the scope of this question; however it could be a good idea considering that this code is part of a large project with many collaborators in your team.

edited Jan 8, 2017 at 11:32

answered Jan 8, 2017 at 11:26

user4244405

1 Comment

user4244405 Over a year ago

If you need a more elaborate answer that includes dynamically setting the values upon window resize event; or even if I should add the write restrictions code - just pop a comment here and I'll add it ;)

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