Question

I don’t really know too much about core JavaScript, just a dot of jQuery. But I know jQuery is not necessary for what I need here:

I want to use the getdate function to find out the server’s day of the week. Then add a bunch of clauses like:

• if its Monday add 6 to the date and return the date in MM/DD/YYYY form.
• if its Tuesday add 5 to the date and return the date in MM/DD/YYYY form.
• if its Wednesday add 4 to the date and return the date in MM/DD/YYYY form.

and so on until Sunday when it will add 0.

So lets say todays Monday, it will return 1/8/2012
And in real dates today’s Sunday so it will really return 1/1/2012

Then I just want to call a document.write function to write the MM/DD/YYYY it returns into my HTML document.

Can anybody help me? I can clarify if you need me to…

Answer 1

getDay() returns the day of the week, Sunday = 0, Monday = 1, etc, etc.

So say today was Monday getDay() would return 1, which means daysToAdd would be 5.

Once we know how many days we want to add we can create a new date and add those days. We do this by getting today in milliseconds and then adding the number of days (daysToAdd) in milliseconds.

We convert days to milliseconds by multiplying by 24*60*60*1000 which is the number of milliseconds in a day.

I add 1 to the month because JavaScript returns 0 based month, but for display purposes we want to format it so that January for example is 1 not zero.

function getEndOfWeek() {
    var today = new Date();
    var weekDay = today.getDay();
    // if you want the week to start on Monday instead of Sunday uncomment the code below
    //weekDay -= 1;
    //if(weekDay < 0) {
    //    weekDay += 7;
    //}
    var daysToAdd = 6 - weekDay;
    var newDate = new Date(today.getTime() + daysToAdd *24*60*60*1000);
    var month = newDate.getMonth() + 1;
    var day = newDate.getDate();
    var year = newDate.getFullYear();
    var formatedDate = month + "/" + day + "/" + year;
    return formatedDate;
}

You could implement in your code like so, JavaScript:

$(function() {
    $("#TheDate").html(getEndOfWeek());
});

Your HTML would be something like this:

The week ends on <span id="TheDate"></span>.

You can find the jsFiddle here: jsFiddle

If you want to adjust the weekday so that you consider Monday the start of the week instead of Sunday you can do the following after you get the weekDay:

weekDay -= 1;
if(weekDay < 0) {
    weekDay += 7;
}