Loop from startdate to enddate from inputs with javascript

Would a loop like this work?:

var current_date = new Date("01/13/2013");
var end_date = new Date("01/20/2013");
var end_date_time = end_date.getTime();

while (current_date.getTime() < end_date_time) {
    console.log(current_date);
    current_date.setDate(current_date.getDate()+1);
}

http://jsfiddle.net/Sn6Ws/

Depending on the format of your textboxes' values, you can set it up like this:

$(document).ready(function () {
    $("#btn").on("click", function () {
        dateLooper(function (cur, end) {
            console.log("Current date: " + cur.toString() + ", End Date: " + end.toString());
        });
    });
});

function dateLooper(callback) {
    var start_date_text = document.getElementById("start_date").value;
    var end_date_text = document.getElementById("end_date").value;

    var current_date = new Date(start_date_text);
    var end_date = new Date(end_date_text);
    var end_date_time = end_date.getTime();

    while (current_date.getTime() < end_date_time) {
        //console.log(current_date);
        callback.call(this, current_date, end_date);
        current_date.setDate(current_date.getDate()+1);
    }
}

http://jsfiddle.net/Sn6Ws/1/

Per your comments that explain the date are in the format "dd/mm/yyyy", you could use something like this:

var start_date_text = document.getElementById("start_date").value;
var start_split = start_date_text.split("/");
if (start_split.length != 3) {
    return false;
}
start_date_text = start_split[1] + "/" + start_split[0] + "/" + start_split[2];

var end_date_text = document.getElementById("end_date").value;
var end_split = end_date_text.split("/");
if (end_split.length != 3) {
    return false;
}
end_date_text = end_split[1] + "/" + end_split[0] + "/" + end_split[2];

to get the dates in the right format before passing them to new Date. Here's an updated jsFiddle that demonstrates it:

http://jsfiddle.net/Sn6Ws/4/

Of course, be careful that if the dates don't come in with the specified format (in case users can type this in or something), the code will most likely throw an error. You can obviously put more checks in to make sure certain things set before proceeding with certain operations (like making sure each item is a number/integer, making sure the days are in the range 1 to 31, etc.). So for that reason, you may want to go the route of regular expressions. At least with regular expressions, you can specify a specific pattern and know whether it matches perfectly or not, and immediately get the values you need to build a date.

Using regular expressions, here's an example that isn't complete but should hopefully help:

function dateLooper(callback) {
    var re = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/;

    var start_date_text = document.getElementById("start_date").value;
    var start_match = re.exec(start_date_text);
    if (start_match) {
        var valid = true;
        // Set `valid` variable based on the following
        // Validate start_match[1] is valid day
        // Validate start_match[2] is valid month
        // Validate start_match[3] is valid year
        if (valid) {
            start_date_text = combineDate(start_match);
        } else {
            return false;
        }
    } else {
        return false;
    }

    var end_date_text = document.getElementById("end_date").value;
    var end_match = re.exec(end_date_text);
    if (end_match) {
        var valid = true;
        // Set `valid` variable based on the following
        // Validate end_match[1] is valid day
        // Validate end_match[2] is valid month
        // Validate end_match[3] is valid year
        if (valid) {
            end_date_text = combineDate(end_match);
        } else {
            return false;
        }
    } else {
        return false;
    }

    var current_date = new Date(start_date_text);
    var end_date = new Date(end_date_text);
    var end_date_time = end_date.getTime();
    var days_spent = 0;

    while (current_date.getTime() < end_date_time) {
        days_spent++;
        callback.call(this, current_date, end_date, days_spent);
        current_date.setDate(current_date.getDate()+1);
    }

    return days_spent;
}

function combineDate(re_match) {
    return re_match[2] + "/" + re_match[1] + "/" + re_match[3];
}

http://jsfiddle.net/Sn6Ws/6/