Javascript Problem

Seachmall

I having a problem with a javascript piece. Its basic objective is, using todays date and day, find out what day the first of the month was. It works like this:

Today is the 10th and a Tuesday. The days are 0=Sunday, 1=Monday etc. To find what day the first of the month was I must subtract 1 from 10 and then subtract the answer of that, 9, from the day, 2. However every time the day reaches minus 1 (or less than 0) is must reset to 6 (which is Sat) and continue subtracting. It shall then land on the answer. So,

10-1=9. 9-2=0 (because it reset). 0=Sunday which the first of the month was. Heres the loop I'm using:

while(date-1 > 0) {
	if(day>0) {
		date--;
		day--;
	}else{
		day = 6;
}
}

For some reason it comes up 6 and continues to run till the browser stops it. Anyone willing to lend a hand?

Thanks,
S.

little_sheep

Seachmall wrote:

I having a problem with a javascript piece. Its basic objective is, using todays date and day, find out what day the first of the month was. It works like this:

Today is the 10th and a Tuesday. The days are 0=Sunday, 1=Monday etc. To find what day the first of the month was I must subtract 1 from 10 and then subtract the answer of that, 9, from the day, 2. However every time the day reaches minus 1 (or less than 0) is must reset to 6 (which is Sat) and continue subtracting. It shall then land on the answer. So,

10-1=9. 9-2=0 (because it reset). 0=Sunday which the first of the month was. Heres the loop I'm using:

while(date-1 > 0) {
	if(day>0) {
		date--;
		day--;
	}else{
		day = 6;
}
}

For some reason it comes up 6 and continues to run till the browser stops it. Anyone willing to lend a hand?

Thanks,
S.

try to display date and day for each while. Javascript has some problème with number and string maybe it's this case.

Inspector Gadget

Off the top of my head, here's a quick and dirty way to do it...

seconds_per_day = 86400;
today = new Date();

first_of_month = today - (today.getDate() * seconds_per_day);
result = first_of_month.getDay();

Haven't tested this, but the theory should be fine.
Gadget.

Seachmall

Little_Sheep,
I threw an alert in the loop to tell me what was happening and everytime it was resetting back to 6 in didn't deduct 1 from date so the additional 1s were adding up. I put a date-- in the if and it works fine. Thanks for the tip.

Thanks anyway gadget.

stipey

This is untested... but I think it should work.

var dayNumber;
var first = new Date();         [COLOR="DarkGreen"]// set to today's date by default.[/COLOR]
first.setDate(1);               [COLOR="DarkGreen"]// first day of the month.[/COLOR]
dayNumber = first.getDay();

Feel free to shoot holes in it....