I have a JavaScript method that call JQuery.get() and i want to return value from itto callee function .. the following is the code :

function CheckExistance(userName) {
        $.get(
            "JQueryPage.aspx", { name: userName },
             function(result) {
                 if (result == "1") {
                     value = true;
                 }
                 else if (result == "0") {
                     value = false;
                 }
                 else if (result == "error") {
                     value = false;
                 }
             }
        );                
        return value;
    }

i want return value; return the value setted in get() function ... i know that get() is asynchronous operation anf i want a solution to do that ?