Example A link with a media attribute: <a href=”https://dwfaisalabad.com?output=print” media=”print and (resolution:300dpi)”> Open media attribute page for print.</a> Try it Yourself » Definition and Usage The media attribute specifies what media/device the linked document is optimized for. This attribute is used to specify that the target URL is designed for special devices (like iPhone) , speech […]
Example Use of the charset attribute in a link: <a charset=”UTF-8″ href=”https://dwfaisalabad.com”>www.dwfaisalabad.com</a> Try it Yourself » Definition and Usage The <a> charset attribute is not supported in HTML5. The charset attribute specifies the character-set of the linked document (the document referenced in the href attribute). Syntax <a charset=”value”> Attribute Values Value Description character_set The character-set of the […]
Example A link to W3Schools.com: <a href=”https://dwfaisalabad.com”>Visit DW Fsd</a> Try it Yourself » More “Try it Yourself” examples below. Definition and Usage The <a> tag defines a hyperlink, which is used to link from one page to another. The most important attribute of the <a> element is the href attribute, which indicates the link’s destination. […]
Example <!DOCTYPE html> <html> <head> <title>Title of the document</title> </head><body> The content of the document…… </body></html> Try it Yourself » Definition and Usage The <!DOCTYPE> declaration must be the very first thing in your HTML document, before the <html> tag. The <!DOCTYPE> declaration is not an HTML tag; it is an instruction to the web browser […]
This chapter describes the different input types for the <input> element. Input Type Text <input type=”text”> defines a one-line text input field: Example <form> First name:<br> <input type=”text” name=”firstname”><br> Last name:<br> <input type=”text” name=”lastname”> </form> Try it Yourself » This is how the HTML code above will be displayed in a browser: First name: Last name: Input Type Password <input type=”password”> defines […]
HTML Tags Ordered Alphabetically = New in HTML5 Tag Description <!–…–> Defines a comment <!DOCTYPE> Defines the document type <a> Defines a hyperlink <abbr> Defines an abbreviation or an acronym <acronym> Not supported in HTML5. Use <abbr> instead. Defines an acronym <address> Defines contact information for the author/owner of a document <applet> Not supported in HTML5. Use <embed> or <object> instead. […]
HTML Form Example First name: Last name: Try it Yourself » The <form> Element The HTML <form> element defines a form that is used to collect user input: <form> . form elements . </form> An HTML form contains form elements. Form elements are different types of input elements, like text fields, checkboxes, radio buttons, submit buttons, and more. […]
Style Guide and Coding Conventions HTML Coding Conventions Web developers are often uncertain about the coding style and syntax to use in HTML. Between 2000 and 2010, many web developers converted from HTML to XHTML. With XHTML, developers were forced to write valid and “well-formed” code. HTML5 is a bit more sloppy when it comes […]
In JavaScript you cannot use these reserved words as variables, labels, or function names: abstract arguments await* boolean break byte case catch char class* const continue debugger default delete do double else enum* eval export* extends* false final finally float for function goto if implements import* in instanceof int interface let* long native new null […]
How to speed up your JavaScript code. Reduce Activity in Loops Loops are often used in programming. Each statement in a loop, including the for statement, is executed for each iteration of the loop. Statements or assignments that can be placed outside the loop will make the loop run faster. Bad: var i; for (i = 0; i […]
Avoid global variables, avoid new, avoid ==, avoid eval() Avoid Global Variables Minimize the use of global variables. This includes all data types, objects, and functions. Global variables and functions can be overwritten by other scripts. Use local variables instead, and learn how to use closures. Always Declare Local Variables All variables used in a function […]
Math.random() Math.random() returns a random number between 0 (inclusive), and 1 (exclusive): Example Math.random(); // returns a random number Try it Yourself » Math.random() always returns a number lower than 1. JavaScript Random Integers Math.random() used with Math.floor() can be used to return random integers. Example Math.floor(Math.random() * 10); // returns a random integer from 0 to […]
JavaScript arrays are used to store multiple values in a single variable. Example var cars = [“Saab”, “Volvo”, “BMW”]; Try it Yourself » What is an Array? An array is a special variable, which can hold more than one value at a time. If you have a list of items (a list of car names, for example), storing […]
JavaScript has only one type of number. Numbers can be written with or without decimals. Example var x = 3.14; // A number with decimals var y = 3; // A number without decimals Try it yourself » Extra large or extra small numbers can be written with scientific (exponent) notation: Example var x = 123e5; // 12300000 var y = 123e-5; // 0.00123 JavaScript Numbers are […]
HTML events are “things” that happen to HTML elements. When JavaScript is used in HTML pages, JavaScript can “react” on these events. HTML Events An HTML event can be something the browser does, or something a user does. Here are some examples of HTML events: An HTML web page has finished loading An HTML input field was changed An […]
JavaScript Arithmetic Operators Arithmetic operators perform arithmetic on numbers (literals or variables). Operator Description + Addition – Subtraction * Multiplication / Division % Modulus (Remainder) ++ Increment — Decrement Arithmetic Operations A typical arithmetic operation operates on two numbers. The two numbers can be literals: Example var x = 100 + 50; Try it Yourself » or variables: Example […]
JavaScript variables are containers for storing data values. In this example, x, y, and z, are variables: Example var x = 5; var y = 6; var z = x + y; Try it Yourself » From the example above, you can expect: x stores the value 5 y stores the value 6 z stores the value 11 Much Like […]
JavaScript comments can be used to explain JavaScript code, and to make it more readable. JavaScript comments can also be used to prevent execution, when testing alternative code. Single Line Comments Single line comments start with //. Any text between // and the end of the line will be ignored by JavaScript (will not be […]
Example var x, y, z; // Statement 1 x = 5; // Statement 2 y = 6; // Statement 3 z = x + y; // Statement 4 Try it Yourself » JavaScript Programs A computer program is a list of “instructions” to be “executed” by a computer. In a programming language, these programming instructions are called statements. A JavaScript program is a list of programming statements. In […]
The <script> Tag In HTML, JavaScript code must be inserted between <script> and </script> tags. Example <script> document.getElementById(“demo”).innerHTML = “My First JavaScript”; </script> Try it Yourself » Old JavaScript examples may use a type attribute: <script type=”text/javascript”>. The type attribute is not required. JavaScript is the default scripting language in HTML. JavaScript Functions and Events A JavaScript function is […]
