access javascript variable from another script

Question

I have the following structure

// script1.js

jQuery(document).ready(function($) {
    var somevar;
    $('somelem').myPlugin();
});


// script2.js

(function($) {
    $.fn.myPlugin = function(options) {

        // access and modify 'somevar' here so that it gets modified
        // in the function which called a plugin

    };
});

• I want the 'somevar' variable to get modified by plugin and I would be able to work with already modified variable further in the plugin caller function's scope.
• I do not want to use global variable.
• I see no use of passing the variable as an option to a plugin as it would become local to a plugin function and modifying would not modify the original variable as I understand.
• I may misunderstand the concept of how javascript works, so any answer appreciated.

Answer 1

You can write function that will set value from variable and then call she in another script.

//script1.js

var somevar;

function setSomevar(value){
somevar = value;
}

function getSomevar(){
return somevar;
}

jQuery(document).ready(function($) {
$('somelem').myPlugin();
});

Now you can call function setSomevar and pass the value to variable. I hope that helps. Best Regards.

Answer 2

When you pass a primitive type, it is passed by value. But, if you pass an object then it'll pass by reference. So, you can do that -

jQuery(document).ready(function($) {
    var somevar = {val: 5};
    $(document).myPlugin(somevar);
    alert(somevar.val);
});


// script2.js

(function($) {
    $.fn.myPlugin = function(options) {
        options.val ++;
        // access and modify 'somevar' here so that it gets modified
        // in the function which called a plugin

    };
})(jQuery);

see the live demo :: http://jsfiddle.net/rifat/EdRFm/

Answer 3

You could let the plugin function return a value and assign that to somevar

somevar = $('someelem').myPlugin();

Or you could pass an callback as parameter to your plugin method

// Script 1
var somevar;
$('someelem').myPlugin(function(newValue) {
    somevar = newValue;
});

// Script 2
$.fn.myPlugin = function(callback) {
    ...
    callback(newValueForSomeVar);
}

Answer 4

you could create a singleton class for your global variables.