Javascript cookies

[Crystatic]

I do not understand this script, please explain the following if possible:

1. Set exdate's date to be the value exdate already pocessed, plus expire days. Is this correct? Where is expiredays defined? (Yes, I see the (expiredays==null) thing in there, is that it?)

2. What does this do? What does escape do?

3.If the webpage's cookie's length is greater than 0. Is this correct?

4.What does this do? I've never seen IndexOf before. Why is the (C_name + "=") thrown in?

5.If c_start is not equal to 1. Is this correct? Where is C_start defined?

6. c_start equals whatever value it already has, plus the length of C_name +1. Is this correct?

7.What does this do?

8. Isn't this defined twice?

9.What does this do? What is unescape?

10. Return what? Nothing?

11. The variable username equals the function getCookie(). Is the parameter the string "username" or the variable username again?

12. What does this do?

[SC_Modder]

First, answer this:

Why in the hell are you using javascript to handle cookies?

[kds]

Yeah, cookies in PHP are SO much easier to understand...

[YonderKnight]

Ok, I have some research to do for a paper so I'm answering all these questions to distract me =p. But I'd take SCM's and KDS's advice, use PHP for cookie handling. Not only is it easier, but it's more secure also.

Originally Posted by Crystatic

1. Set exdate's date to be the value exdate already pocessed, plus expire days. Is this correct? Where is expiredays defined? (Yes, I see the (expiredays==null) thing in there, is that it?)

That's correct. Expiredays is a parameter of the function "SetCookie." Look at the first line: "function setCookie(c_name,value,expiredays)"
This is basically defining a function with those 3 parameters, a user will call it using something like "setCookie('somename','poop',20)". This will set c_name, value, and expiredays to those values accordingly.

Originally Posted by Crystatic

2. What does this do? What does escape do?

Escape(value) replaces every character except letters with their %xx code equivilants. You've probably seen this a lot in URL's, for example "www.something.com/some%20gay%20page.htm". %20 is the hex encoding for a space.

Cookies need to be in some format like "cookieName=cookieValue;cookieName2=cookieValue2.. ..etc"
The first line of code you asked about defines the cookie to be something like
c_name=valueThatIsEscaped;expires=somegaydate

Originally Posted by Crystatic

3.If the webpage's cookie's length is greater than 0. Is this correct?

Correct

Originally Posted by Crystatic

4.What does this do? I've never seen IndexOf before. Why is the (C_name + "=") thrown in?

IndexOf basically searches a string for another string and returns where it found the first location of the string you wanted to search for. That line basically finds where "c_name=" is located.

For example:
var string="poopy";
stuff = string.indexOf("y");

This will return 4, because the letter y first occurs as the 4th letter of the string.

Originally Posted by Crystatic

5.If c_start is not equal to 1. Is this correct? Where is C_start defined?

Almost. It checks if C_start is not equal to -1, not 1. C_start is defined in the previous line. It's equal to indexOf(c_name+"="). So basically, if indexOf looked through the document cookie and couldn't find the name the user specified in c_name, c_start will be -1.

This line basically means if the cookie was found, then continue.

Originally Posted by Crystatic

6. c_start equals whatever value it already has, plus the length of C_name +1. Is this correct?

Yep. The new position that c_start contains is the position where the value of the cookie actually starts.

Originally Posted by Crystatic

7.What does this do?

This finds the end of the cookie data by searching for a ";" (which is used to specify the end of the cookie). c_start is thrown in there to tell indexOf to start searching from the beginning of c_start, so you won't find the end of a cookie value that actually came before the one you want.

Originally Posted by Crystatic

8. Isn't this defined twice?

No. This line checks if c_end is equal to -1. There is a MAJOR difference between
something=1; < this line sets something equal to 1.
and
something==1; < this line checks if something is equal to 1.

Originally Posted by Crystatic

9.What does this do? What is unescape?

Ok, if you remember when we actually set the cookie, we had to use escape(value). This replaces all the spaces and other characters and stuff with things like %20. Now to actually read it, we'll have to unescape it, which will convert it back into regular characters.

Substr basically "cuts" out everything between c_start and c_end. This is the actual value of the cookie.

This line returns that new value. So if the user calls
asdf = getCookie("poop")
asdf will now be equal to that value that the cookie holds.

Originally Posted by Crystatic

10. Return what? Nothing?

Yes, if you look way back up to the if() statement, if the cookie search didn't find anything, the function will return nothing. If it did, it'll return the actual value of the cookie.

Originally Posted by Crystatic

11. The variable username equals the function getCookie(). Is the parameter the string "username" or the variable username again?

The parameter sent to getCookie is the string "username". The variable username will hold the value that the cookie holds under "username".

Originally Posted by Crystatic

12. What does this do?

This sets the cookie "username" to be equal to the value in the variable username. And it sets the cookie to expire in 365 more days (a year).


Hope that helps. You didn't actually need to know all of that to set/get cookies. You really only had to know how to call the function that they provided you (the last part is just an example). The actual functions may seem confusing, but most of this stuff is just string manipulation (just searching through strings and cutting stuff out).

[Crystatic]

Originally Posted by SC_Modder

First, answer this:

Why in the hell are you using javascript to handle cookies?

I was reading a tutorial for javascript, and cookies were the next lesson.


So, can javascript do anything that PHP can't?

[lpxxfaintxx]

Javascript can do loads of stuff that PHP can't... but you can use javascript WITH php.

[Ganondorf]

Originally Posted by lpxxfaintxx

Javascript can do loads of stuff that PHP can't... but you can use javascript WITH php.

And vice versa.

[SC_Modder]

There are a lot of differences between PHP and javascript that they are barely comparable. Yeah, sure, they are both interpreted languages and they both have C style programming, but their purposes are completely different.

[Crystatic]

[Bump]

What if the place i'm working with is not PHP enabled? Is there something I could embed into an Html page that would be just as active with the server as PHP is?

[Ganondorf]

You can install PHP manually if your allowed to.