How to make a variable which is inside a function global?

Following is my javascript function, I want to use variable selected outside function, but I am getting selected not defined error in console of inspect element. window.yourGlobalVariable is not solving my problem.

function showMe(pause_btn) {
    var selected = [];
    for (var i = 0; i < chboxs.length; i++) {
        if (chboxs[i].checked) {
            selected.push(chboxs[i].value);
        }
    }
}

If you really want it to be global, you have two options:

var selected;
function showMe(pause_btn) {
    selected = [];
    for (var i = 0; i < chboxs.length; i++) {
        if (chboxs[i].checked) {
            selected.push(chboxs[i].value);
        }
    }
}

function showMe(pause_btn) {
    window.selected = [];
    for (var i = 0; i < chboxs.length; i++) {
        if (chboxs[i].checked) {
            selected.push(chboxs[i].value); // Don't need `window.` here, could use it for clarity though
        }
    }
}

But , I would avoid making it global. Either have showMe return the information:

function showMe(pause_btn) {
    var selected = [];
    for (var i = 0; i < chboxs.length; i++) {
        if (chboxs[i].checked) {
            selected.push(chboxs[i].value);
        }
    }
    return selected;
}

...and then where you need it:

var selected = showMe();

...or declare it in the scope containing showMe , but not globally. Without context, that looks exactly like #1 above; here's a bit of context:

(function() {
    var selected;
    function showMe(pause_btn) {
        selected = [];
        for (var i = 0; i < chboxs.length; i++) {
            if (chboxs[i].checked) {
                selected.push(chboxs[i].value);
            }
        }
        return selected;
    }

    // ...other stuff that needs `selected` goes here...
})();

The outer anonymous function is a "scoping function" which means that selected isn't global, it's just common to anything in that function.

Do this:

var selected;

function showMe(pause_btn) {
    selected = [];
    for (var i = 0; i < chboxs.length; i++) {
        if (chboxs[i].checked) {
            selected.push(chboxs[i].value);
        }
    }
}

You can actually skip the var selected; line but I prefer declaring my variables.

Dont use this;

 selected = [];

it is a bug of javascript

window.selected = []; 

inside your function.

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