Skip to main content

Javascript Variable


JavaScript Variables


As with algebra, JavaScript variables are used to hold values or expressions.

A variable can have a short name, like x, or a more descriptive name, like carname.

Rules for JavaScript variable names:

  • Variable names are case sensitive (y and Y are two different variables)
  • Variable names must begin with a letter or the underscore character
The Main thing of javascript variable is u can store any kind of value in that variable even it is string or numeric value.

Note: Because JavaScript is case-sensitive, variable names are case-sensitive.


Example

A variable's value can change during the execution of a script. You can refer to a variable by its name to display or change its value.


var m;

var p;

m = "testing for javascript" ;

p=15;

Comments

Popular posts from this blog

Number Format In Javascript

Number.toFixed() :                                 Formats any number for "x" number of trailing decimals. The number is rounded up, and "0"s are used after the decimal point if needed to create the desired decimal length.   var profits=2489.8237 profits.toFixed(3) //returns 2489.824 (round up) profits.toFixed(2) //returns 2489.82 profits.toFixed(7) //returns 2489.8237000 (padding)   Number.toPrecision() :                                   Formats any number so it is of "x" length. Also called significant digits. A decimal point and "0"s are used if needed to create the desired length.   var anumber=123.45 anumber.toPreci...

Use of indexOf and charAt in javascript

indexOf(): The indexOf() method returns the position of the first occurrence of a specified value in a string. This method returns -1 if the value to search for never occurs. example :  <script type="text/javascript"> var str="Hello world!"; document.write(str.indexOf("d") + "<br />"); document.write(str.indexOf("WORLD") + "<br />"); document.write(str.indexOf("world")); </script> Output : 10 -1 6 charAt() The charAt() method returns the character at the specified index in a string. The index of the first character is 0, and the index of the last character in a string called "txt", is txt.length-1 <script type="text/javascript"> var str = "Hello world!"; document.write("First character: " + str.charAt(0) + "<br />"); document.write("Last character: " + str.charAt(str.l...

Find extension of file in Php

In our scripting sometimes we need to upload such documents , at that time there should be a validation for proper file. For example in your system suppose there is a field for image upload , that is obvious in that field only image formats are allowed (jpg,jpeg,png,gif etc.). At that time you have to give a validation on that field. In Php to find the extension and validation here is your code :  <?php                     $image = $_FILES["file"]["name"];    // to fetch the file name             $n1=strripos($image,".");                     // to find the last position of "."             $v1 =substr($image,$n1);                  ...