Global javascript variable inside document ready

Question

Which is the right way of declaring a global javascript variable  The way I m trying it  doesn t work    document  ready function          var intro       if      intro check   is   checked              intro   true              intro   wrap   lt div class  disabled  gt  lt  div gt                     intro check   change function            if this checked                intro   false                  enabled   removeClass  enabled   addClass  disabled              else               intro   true              if     intro   exists                          disabled   removeClass  disabled   addClass  enabled                   else                       intro   wrap   lt div class  disabled  gt  lt  div gt                                          console log intro

User · Answer

JavaScript has Function-Level variable scope which means you will have to declare your variable outside   document  ready   function   Or alternatively to make your variable to have global scope  simply dont use var keyword before it like shown below  However generally this is considered bad practice because it pollutes the global scope but it is up to you to decide     document  ready function        intro   null     it is in global scope now     To learn more about it  check out    Explaining JavaScript Scope And Closures

User · Answer

You can define the variable inside the document ready function without var to make it a global variable  In javascript any variable declared without var automatically becomes a global variable    document  ready function         intro     something         although you cant use the variable immediately  but it would be accessible to other functions

User · Answer

If you re declaring a global variable  you might want to use a namespace of some kind   Just declare the namespace outside  then you can throw whatever you want into it   Like this     var MyProject         document  ready function         MyProject intro            MyProject intro    something        console log MyProject intro       something

User · Answer

declare this var intro   outside of   document  ready   because    document  ready   will hide your variable from global scope  Code var intro     document  ready function         if      intro check   is   checked              intro   true              intro   wrap   lt div class  quot disabled quot  gt  lt  div gt                    intro check   change function            if this checked                intro   false                  enabled   removeClass  enabled   addClass  disabled              else               intro   true              if     intro   exists                          disabled   removeClass  disabled   addClass  enabled                   else                       intro   wrap   lt div class  quot disabled quot  gt  lt  div gt                                           According to  Zakaria comment Another way  window intro   undefined     document  ready function         if      intro check   is   checked              window intro   true              intro   wrap   lt div class  quot disabled quot  gt  lt  div gt                    intro check   change function            if this checked                window intro   false                  enabled   removeClass  enabled   addClass  disabled              else               window intro   true              if     intro   exists                          disabled   removeClass  disabled   addClass  enabled                   else                       intro   wrap   lt div class  quot disabled quot  gt  lt  div gt                                           Note console log intro    outside of DOM ready function  currently you ve  will log undefined  but within DOM ready it will give you true  false  Your outer console log execute before DOM ready execute  because DOM ready execute after all resource appeared to DOM i e after DOM is prepared  so I think you ll always get absurd result   According to comment of  W0rldart  I need to use it outside of DOM ready function  You can use following approach  var intro   undefined     document  ready function         if      intro check   is   checked              intro   true          introCheck                intro   wrap   lt div class  quot disabled quot  gt  lt  div gt                    intro check   change function             if  this checked                intro   true            else               intro   false                    introCheck                  function introCheck         console log intro      After change the value of intro I called a function that will fire with new value of intro

User · Answer

Use window intro    value   inside the ready function   value  could be void 0 if you want it to be undefined

User · Answer

Use window intro inside of   document  ready

User · Answer

like this  put intro outside your document ready  Good discussion here  http   forum jquery com topic how-do-i-declare-a-global-variable-in-jquery  thecodeparadox is awesomely fast  P anyways    var intro     document  ready function            if      intro check   is   checked              intro   true              intro   wrap   lt div class  disabled  gt  lt  div gt                     intro check   change function            if this checked                intro   false                  enabled   removeClass  enabled   addClass  disabled              else               intro   true              if     intro   exists                          disabled   removeClass  disabled   addClass  enabled                   else                       intro   wrap   lt div class  disabled  gt  lt  div gt

User · Answer

Unlike another programming languages  any variable declared outside any function automatically becomes global    lt script gt     declare global variable var   foo    123    function   test         foo is global and visible here  alert   foo        so  it will alert  123    test      lt  script gt    You problem is that you declare variable inside ready   function  which means that it becomes visible  in scope  ONLY inside ready   function  but not outside   Solution  So just make it global  i e declare this one outside   document  ready function

[javascript] Global javascript variable inside document.ready

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