Scratch

Hardmath, I like the NEW! idea 

Last edited by sparks (2011-11-12 14:09:26)

That just hurts my eyes 

.

Last edited by WindowsExplorer (2011-11-13 05:02:51)

Hardmath123 wrote:

WindowsExplorer wrote:

.

AAA! Seizure!

...

If that gave you a seizure check out this

Some JS stuff:


Use MDN and not w3schools


In almost every case, it is better to use the identity operator than the equality operator[/url] because the equality operator behaves strangely. Leaving out semicolons is a bad idea, because odd things can happen:

var a;
a = 2
(a + 2).toString();
// throws a TypeError because 2 is treated as a function
// same as:
a = 2(a + 2).toString();

Self-evaluating (or self-invoking, etc.) functions are closures (functions without names) that call themselves in the expression they're created in. They're incredibly useful for controlling scope:

(function () { // construct a closure...
var a = 2;
console.log(a); // 2
})(); // ... and call it
console.log(a); // a is undefined

Method calls are really just a property access + a function call:

(function () {
var foo = window.alert; // property access
foo(2); // function call
})();

The "global scope" means the window object in most cases - it's the place variables are looked up/defined if they're not found elsewhere:

var foo = 2; // window.foo = 2
(function () {
var bar = 3;
console.log(bar); // 3
console.log(foo); // 2
})();

The "window" object actually has a "window" property, which is what is being accessed when you use window without defining it elsewhere. It is perfectly legal to do that anywhere but in the global scope:

window = 'foo';
console.log(window); // the window object
(function () {
var window = 2;
console.log(window); // 2
})();

JavaScript actually uses prototypal inheritance (a different system of inheritance than classical, which is what programming languages like Java and Smalltalk use). This means that any object can inherit from any other object:

var foo = { // object literal; constructs an Object with the properties between the braces
    a: 2
};
var bar = Object.create(foo); // create a new Object which inherits from foo

// properties which are not part of objects are looked up in their prototype, and that object's prototype, and so on
console.log(bar.a); // 2

// you can change an object's prototype's property (or add/remove) one,
// and the change is visible in the objects which inherit from it
foo.a = 8;
console.log(bar.a); // 8

// it's fine to define properties that are present in an object's prototype
bar.a = 3;
console.log(bar.a); // 3

// ... but doing this has no effect on the prototype
console.log(foo.a); // 8

The new keyword creates a new object which inherits from its argument's prototype, then calls its argument (a function) with that object as the value of "this"

function F() {
    this.a = 2;
}
var foo = new F();
// same as...
var foo = F.apply(Object.create(F.prototype));

Apply is a method of Function objects which applies the function to the given arguments (an array, the 2nd argument) using the 1st argument as the "this" value)

When making constructors, use the prototype object, because:
1) all instances of the constructor inherit their methods from one object (this uses less memory)
2) all instances' methods are identical--they are the same object, rather than being functions which have the same contents

function UsePrototype() {}
UsePrototype.aMethod = function () {
    console.log('hi');
};
function DontUsePrototype() {
    this.aMethod = function () {
        console.log('hi');
    };
}
var a = new UsePrototype();
var b = new UsePrototype();
a.aMethod === b.aMethod; // true

a = new DontUsePrototype();
b = new DontUsePrototype();
a.aMethod === b.aMethod; // false

The naming convention is to capitalize constructors:

function Constructor() {} // constructor!
new Constructor();
function someFunction() {} // not a constructor!
someFunction();

EDIT: I will probably write a prototype-based JS tutorial soon, explaining things in more detail.

Last edited by nXIII (2011-11-13 15:24:18)

hmm this is pretty cool! I have some html things worth posting.

Nice tutorial, Hardmath123, IDK if this is just because of my viewpoint, but I would class that as a moderate not hard tutorial    It's very good!

Last edited by sparks (2011-11-14 18:44:06)

I need help. (I'm PF, btw)
Um, so yes. This is a blog app that stores each post in the xml file, posts.xml.
Currently, it is not reading....

<?php
//blogify.php
//Blog App.
//Made by ProgrammingFreak
$app = "Blogify";
$style = "
#blog_app{
max-height: 600;
max-width:900;
height: 600;
width: 900;
display: none;
background-color: #4B79AD;

}
#blog_app button{
background: #1e5799;
background: -moz-linear-gradient(top,  #1e5799 0%, #2989d8 28%, #207cca 51%, #7db9e8 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#1e5799), color-stop(28%,#2989d8), color-stop(51%,#207cca), color-stop(100%,#7db9e8));
background: -webkit-linear-gradient(top,  #1e5799 0%,#2989d8 28%,#207cca 51%,#7db9e8 100%);
background: -o-linear-gradient(top,  #1e5799 0%,#2989d8 28%,#207cca 51%,#7db9e8 100%);
background: -ms-linear-gradient(top,  #1e5799 0%,#2989d8 28%,#207cca 51%,#7db9e8 100%);
background: linear-gradient(top,  #1e5799 0%,#2989d8 28%,#207cca 51%,#7db9e8 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#1e5799', endColorstr='#7db9e8',GradientType=0 );

border-style:solid;
border-color:#1e5799;
color: #fff;
}
#menu{
background-color:#1e5799;
width: 900px;
}
#menu img{
    margin-left: 5px;
    margin-top: 5px;
    margin-bottom: -5px;
}
";
echo <<<_END
    <html><head><style>$style</style>
        <script src="http://code.jquery.com/jquery-latest.js"></script>
        <script type="text/javascript">
        $(document).ready(function(){
        $.get("data.php", function(data){
                $("#blog_app").fadeIn(2000);
                $('#blog_app').html(data);
        });

        });
        if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.open("GET","pages.xml",false);
xmlhttp.send();
xmlDoc=xmlhttp.responseXML;

$("#content").html(xmlDoc.childNodes[0].nodeValue); 
$("#content").html("hello"); 
    </script>
    </head><body>
    <div id='blog_app'>
    </div>

    </body></html>
_END;
?>

//posts.xml
<posts>
    <post>
    <author>%uservar%</author>
    <content>Welcome to Blogify.</content>
    </post>
</posts>

<?php
//data.php
echo <<<_END
        <div id="menu">
        <img src="logo.png" height="20px" width="20px"/>
        <button id='new'>New Post</button><button id='del' onclick>Delete Post</button>
        </div>
        <div id="content"></div>
_END;
?>

Thanks. 

Has it read the xml file before? If it has, I'm not sure. If it hasn't, maybe put the file into a variable?

Magnie wrote:

Has it read the xml file before? If it has, I'm not sure. If it hasn't, maybe put the file into a variable?

Okay, I'll try that...

In true search engine guruing and great memory, I am posting this question in a relevant thread!

Does anyone know much about cookies? I wanted to get cookie based login working on my website. Then I got really confused.

See, cookies are just little text files stored on your computer. So what's to stop me storing a cookie with the username of the last login in it? Nothing. But then the user could simply change the contents of the cookie with a text-editor so that the name matches another user, then get logged in AS THEM 

Similarly, if I stored the password too, that's a huge security hole for THEM as that cookie can then be used by anyone to log in, just by copying it. No web pages I have found seem to answer this problem, so how can I use cookies for logging in without posing a security risk for either myself or the user????????

Thanks,

Sparks

Right. First of all, there is no such thing as true random, so what do you mean by that? Will the php rand() function do? And in that case, wouldn't a hash of their password do as well? (thank you    )

nXIII wrote:

sparks wrote:

In true search engine guruing and great memory, I am posting this question in a relevant thread!

Does anyone know much about cookies? I wanted to get cookie based login working on my website. Then I got really confused.

See, cookies are just little text files stored on your computer. So what's to stop me storing a cookie with the username of the last login in it? Nothing. But then the user could simply change the contents of the cookie with a text-editor so that the name matches another user, then get logged in AS THEM 

Similarly, if I stored the password too, that's a huge security hole for THEM as that cookie can then be used by anyone to log in, just by copying it. No web pages I have found seem to answer this problem, so how can I use cookies for logging in without posing a security risk for either myself or the user????????

Thanks,

Sparks

You could hash the password and store that and the username (or use a random key, although just hashing means you don't need to store any additional data); alternatively you could store the session ID in a cookie. That way, if the cookie was copied to another computer, it would only work while the user was still logged in.

That's a good idea! Wouldn't the session id change when the session expires though?