Creating a variable, with a variable in an each loop - jQuery

As others have pointed out, using an {} with square bracket notation will simplify this task greatly.

Something like this:

var myobj = {},
    prefix = 'my_cool_var';

for(var i = 0, len = 10; i < len; i++) {
    myobj[prefix + i] = undefined; // { my_cool_var + i : undefined }
}

// Setters - dot notation and square bracket
myobj.my_cool_var1 = "Hello!";
myobj['my_cool_var2'] = "Hello 2!";

// Getters - dot notation and square bracket
alert(myobj.my_cool_var1); // alerts Hello!
alert(myobj['my_cool_var2']); // alerts Hello 2!

Now, if you needed to expose the variables in a global scope (yuck - but hey, sometimes you gotta) so you don't need to specify an object (myobj), you can use window with square bracket notation in your for loop.

var prefix = 'my_global_var';

for(var i = 0, len = 10; i < len; i++) {
    window[prefix + i] = undefined; // creates global, my_global_var + i = undefined
}

my_cool_var1 = "Hello!";
alert(my_cool_var1); // alerts Hello!

Finally, if you search the web deep enough, you'll find eval examples like this:

var prefix = 'my_evil_var';

for(var i = 0, len = 10; i < len; i++) {
    // Don't do this. Use square bracket notation with window, if you need a global.
    eval(prefix + i + '= undefined') // creates global, my_evil_var + i = undefined
}

my_evil_var = "Eval abuse is bad!!";
alert(my_evil_var1); // alerts Eval abuse is bad!!

Hope this helps!

Just make use of the json in this context,

var $counter= 0;
var $newVar = {};

$('.selector').each(function(){
   $counter += 1;
   $newVar['newVariable-'+ ($counter)] = null;
});

so you can access it like $newVar.newVariable-1,.. $newVar.newVariable-N And please note that this is the best practice, we could do as you asked by accessing the window object, but that is not recommended.