variable names

The name of the variable in JavaScript imposed only two limitations.

The name can consist of letters, numbers, symbols, $, and _
The first character must not be a digit.
For example:

var myName;
var test123;

that are especially interesting – the dollar ‘$’ and the underscore ‘_’ are the same as ordinary characters, like letters:

var $ = 5;  // оDeclared a variable called '$'
2 var _ = 15; //  Variable named'_'
3
4 alert($);

And these variables would be wrong:

var 1a; // beginning can not be a digit
var my-name; //hyphen '-' is not allowed symbol

reserved Names

There is a list of reserved words that can not be used when naming variables, as they are used by the language itself, for example: var, class, return, implements, and others.

Some of the words, for example, class, are not used in modern JavaScript, but they are engaged in the future. Some browsers allow you to use them, but it can lead to errors.

The following example will work in many older browsers that allow the use of the word ‘class’ and will not work in today. They will be given a syntax error, try, run:

var class = 5;
alert(class);

The correct choice of name

The correct choice of a variable name – one of the most important and difficult things in programming that distinguishes the novice from the guru.

The fact that most of the time we spend not on the original coding, and its development.

What is development? This is when I wrote the code yesterday and today (or a week) come and want to change it. For example, to display a message not so, and commercials .. Processed goods differently, add functionality .. And where I have it stored message? ..

Much easier to find the data you need, if they are correctly labeled, ie variable named correctly.

Rule 1: There is no transliteration. English only.
unacceptable:

var moiTovari;
var cena;
var ssilka;
suit:

var myGoods;
var price;
var link;
If you suddenly do not know English – it’s time to learn. All the same, in fact have to …

Rule 2: Use only the short name for the variable “local”.
Is a variable names multicarrier no meaning, such as a, e, p, mg – can be used only if they are used in a code fragment, and their use is obvious.

In general, the variable name should be descriptive. Sometimes it is necessary to use a few words.

Rule 3: The variables of several words written vmesteVotTak.
For example:

var borderLeftWidth;
This method of recording is called “camel notation” or, in English, «camelCase».

There is an alternative standard, when a few words are written with an underscore ‘_’:

var border_left_width;
JavaScript is used mainly in one borderLeftWidth, particularly in embedded language and browser functions. Therefore, it is advisable to stay on it.

Another reason to use “camel notation” – write to it a little shorter than the c underlined, as do not need to insert “_”.

Usually the last thing. The variable name must conform to the most well-stored in its data.
Inventing these names – both short and precise, comes with experience, but only if you consciously strive to do so.

 

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Window Manipulation in JavaScript

Window Manipulation in JavaScript

While opening windows in HTML is very handy, it’s also limiting; the browser controls how the window looks. You have no control over the size of the window or what the window looks like. Happily, JavaScript gives you this control.

Here’s how:

1 window.open("URL","name","features");

This statement opens a window with the URL that you list as the first parameter in the method call. Above it’s called ” URL,”

The second parameter of the method call is the window’s name. This is just like the name we saw in the last page. If you open a window and there’s already a window open with the same name, the URL in youropen statement will be sent to that open window.

The third parameter, features, is a list of the different components a window can have. It’s an optional parameter, so let’s do some examples with the first two parameters before checking out features.

Here are some examples of using JavaScript to open windows.

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Javascript Tutor – Lesson 2

Variables.

What’s a variable? Let’s suppose x=5.

x is a variable. The statement x=5 declares that the value of x is now 5. Can x be something else? Sure, x=6. Now x equals 6. (Hence the name “variable”… it’s value can vary.)

Can a variable be something other than a number? Sure. How about x=”Joe”. Now x equals the string “Joe”. (A string by the way is a string of characters… and strings are always enclosed in quotes.)

Can the name of a variable be something other than a letter like x? Sure, myname=”Joe”. Simple.

How can we incorporate this new found knowledge into our function? Easy…

<html>
<head>
<title></title>

<script type="text/javascript">

function HelloWorld()
{
   myname = "Joe";
   alert(myname);
}

</script>

</head>
<body>

<a href="javascript:HelloWorld()">Hello</a>

</body>
</html>

(Note again that strings are always enclosed in quotes, but variables are not.)

What we have called is the alert method. Think of a method as a command. Javascript has many methods.

We could make it say Hello + variable…

<html>
<head>
<title></title>

<script type="text/javascript">

function HelloWorld()
{
   myname = "Joe";
   alert("Hello " + myname);
}

</script>

</head>
<body>

<a href="javascript:HelloWorld()">Hello</a>

</body>
</html>
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JavaScript – Lesson 1. Concepts

JavaScript programming language was developed by Netscape in collaboration with Sun Microsystems and anansirovan in 1995. JavaScript is used to create interactive html-documents. Main areas of use of JavaScript:

Making pages dynamic, ie pages, the content of which may change after loading.

Verification of user forms.

Decision “local” tasks using scripts.

JavaScript-code – the basis of most Ajax-applications.

JavaScript allows you to create applications that run on the client side, ie These applications run on the user’s computer browser

Programs (scripts) are processed in this language interpreter built-in browser. Unfortunately, not all scripts are executed correctly in all browsers, so test your javascript-programs in different browsers. JavaScript is case sensitive, ie uppercase and lowercase letters of the alphabet are considered different characters. Before you start writing the script, you should be familiar with the basic concepts, such as literals, variables, and expressions.

images

 

JavaScript

Hi guys!!!!Consider one of the most popular programming languages ​​JavaScript

Javascript – NOT java, but quite another language. He seems to say, but no more. We have your standard javascript: ECMAScript. Someone said that javascript is similar to Python, someone talks about similarities with languages ​​Ruby, Self. The truth is that the javascript itself. This is really a special language

Main areas of use JavaScript as follows:
the creation of dynamic, interactive Web pages, ie, pages whose content may change after loading the document;
Verification of user forms before forwarding them to the server;
decision “local” tasks using scripts and some other areas.

Google
image

cursor

cursor Ustanavlivaet cursor shape when it is within the cell. The cursor depends on the operating system and installed options.

Before you take the opportunity to alter the cursor, choose, and whether it will be used to the place. Many users of such changes can be misleading when, for example, instead of the traditional hand that appears when you hover over a link, there is something else. In most cases, it is better to leave everything as it is.

!!!!!!!!!

Helloeveryone! I’d like to create my own web-site, but first I need to learn programming. I’ve made a research and found quite good site with tutorials.
Well, I’m starting with first step

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