Question

my problem with the following javascript function:

function ValidateDates() {

var valid = false;
birthD = $("#cp1_txtBirthDate").val();
initialD = $("#cp1_txtInitialDate").val();
var regexp = new RegExp("^([1-9]|(0|1|2)[0-9]|30)(/)([1-9]|1[0-2]|0[1-9])(/)((20|19|18)[0-9]{2})$");

if (birthD != "__/__/____" && initialD != "__/__/____") {
    if (regexp.test(initialD) && regexp.test(birthD)) {

        $.get("ValidateDates.aspx?BirthD=" + birthD + "&InitialD=" + initialD, function (data) {
            if (data == 0) {
                valid = true;

                $("#Dates_span").html("");
            }

            else {
                $("#Dates_span").html("*" + data);
                valid = false;

            }

        });

    }
}

return valid;
}

here when i check the variable valid i found it “false” even if its true, because the initial for it is false from the beginning of function so how to solve it and what is wrong?

Answer 1

When you’re doing an asynchronous call, you can’t return a value like that. Instead, you should pass in a callback:

function ValidateDates(callback) {

    var valid = false;
    birthD = $("#cp1_txtBirthDate").val();
    initialD = $("#cp1_txtInitialDate").val();
    var regexp = new RegExp("^([1-9]|(0|1|2)[0-9]|30)(/)([1-9]|1[0-2]|0[1-9])(/)((20|19|18)[0-9]{2})$");

    if (birthD != "__/__/____" && initialD != "__/__/____") {
        if (regexp.test(initialD) && regexp.test(birthD)) {

            $.get("ValidateDates.aspx?BirthD=" + birthD + "&InitialD=" + initialD, function(data) {
                if (data == 0) {
                    valid = true;

                    $("#Dates_span").html("");
                }

                else {
                    $("#Dates_span").html("*" + data);
                    valid = false;

                }
                callback(valid);
            });
        }
    }
}

Then, call it like:

ValidateDates(function(isValid)
{
   // Do something with isValid
});