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('<div class="disabled"></div>');
    };

    $('.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('<div class="disabled"></div>');
            }
        }
    });
});

console.log(intro);

Answer 1

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('<div class="disabled"></div>');
    };
    $('.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('<div class="disabled"></div>');
            }
        }
    });
});

---

According to @Zakaria comment

Another way:

window.intro = undefined;

$(document).ready(function() {
    if ($('.intro_check').is(':checked')) {
        window.intro = true;
        $('.intro').wrap('<div class="disabled"></div>');
    };
    $('.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('<div class="disabled"></div>');
            }
        }
    });
});

---

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('<div class="disabled"></div>');
    };
    $('.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.

Answer 2

Use window.intro inside of $(document).ready().