Column Object The Column object represents an HTML <col> element. Access a Column Object You can access a <col> element by using getElementById(): Example var x = document.getElementById(“myCol”); Try it Yourself » Create a Column Object You can create a <col> element by using the document.createElement() method: var x = document.createElement(“COL”); Column Object Properties Property Description span […]
The navigator object contains information about the browser. Note: There is no public standard that applies to the navigator object, but all major browsers support it. Navigator Object Properties Property Description appCodeName Returns the code name of the browser appName Returns the name of the browser appVersion Returns the version information of the browser cookieEnabled Determines […]
An HTMLCollection object is an array-like list of HTML elements. Methods like the getElementsByTagName() returns an HTMLCollection. Properties and Methods The following properties and methods can be used on a HTMLCollection object: Property / Method Description item() Returns the element at the specified index in an HTMLCollection length Returns the number of elements in an […]
When an HTML document is loaded into a web browser, it becomes a document object. The document object is the root node of the HTML document. Document Object Properties and Methods The following properties and methods can be used on HTML documents: Property / Method Description activeElement Returns the currently focused element in the document addEventListener() […]
The Attr Object In the HTML DOM, the Attr object represents an HTML attribute. An HTML attribute always belongs to an HTML element. The NamedNodeMap Object In the HTML DOM, the NamedNodeMap object represents an unordered collection of an elements attribute nodes. Nodes in a NamedNodeMap can be accessed by name or by index (number). Properties and Methods Property […]
JavaScript Strings A JavaScript string stores a series of characters like “John Doe”. A string can be any text inside double or single quotes: var carname = “Volvo XC60”; var carname = ‘Volvo XC60’; String indexes are zero-based: The first character is in position 0, the second in 1, and so on. For a tutorial about Strings, read our JavaScript […]
JavaScript Statements In HTML, JavaScript statements are “instructions” to be “executed” by the web browser. This statement tells the browser to write “Hello Dolly.” inside an HTML element with id=”demo”: Example document.getElementById(“demo”).innerHTML = “Hello Dolly.”; Try it Yourself » For a tutorial about Statements, read our JavaScript Statements Tutorial. JavaScript Statement Identifiers JavaScript statements often start with a statement […]
RegExp Object A regular expression is an object that describes a pattern of characters. Regular expressions are used to perform pattern-matching and “search-and-replace” functions on text. Syntax /pattern/modifiers; Example var patt = /dwfaisalabad/i Example explained: /dwfaisalabad/i is a regular expression. dwfaisalabad is a pattern (to be used in a search). i is a modifier […]
JavaScript operators are used to assign values, compare values, perform arithmetic operations, and more. JavaScript Arithmetic Operators Arithmetic operators are used to perform arithmetic between variables and/or values. Given that y = 5, the table below explains the arithmetic operators: Operator Description Example Result in y Result in x Try it + Addition x = y […]
JavaScript Numbers 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 = 34; // A number without decimals Extra large or extra small numbers can be written with scientific (exponent) notation: Example var x = 123e5; // 12300000 var y = 123e-5; // 0.00123 For a tutorial about JavaScript […]
Server-Sent Events allow a web page to get updates from a server. Server-Sent Events – One Way Messaging A server-sent event is when a web page automatically gets updates from a server. This was also possible before, but the web page would have to ask if any updates were available. With server-sent events, the updates […]
Math Object The Math object allows you to perform mathematical tasks. Math is not a constructor. All properties/methods of Math can be called by using Math as an object, without creating it. Syntax var x = Math.PI; // Returns PI var y = Math.sqrt(16); // Returns the square root of 16 For a tutorial about the Math object, read […]
JSON (JavaScript Object Notation) JSON is a format for storing and transporting data. JSON is text, and text can be transported anywhere, and read by any programming language. JavaScript Objects can be converted into JSON, and JSON can be converted back into JavaScript Objects. This way we can work with the data as JavaScript objects, with no complicated […]
The JavaScript global properties and functions can be used with all the built-in JavaScript objects. JavaScript Global Properties Property Description Infinity A numeric value that represents positive/negative infinity NaN The NaN property represents “Not-a-Number” value. This property indicates that a value is not a legal number. The NaN property is the same as the Number.Nan […]
Error Object The Error object provides error information when an error occurs. Example In this example we have written “alert” as “adddlert” to deliberately produce an error. Return the error name and a description of the error: try { adddlert(“Welcome”); } catch(err) { document.getElementById(“demo”).innerHTML = err.name + “<br>” + err.message; } Try it Yourself » For a tutorial about JavaScript […]
JavaScript Booleans JavaScript booleans can have one of two values: true or false. The Boolean() Function You can use the Boolean() function to find out if an expression is true: Example Boolean(10 > 9) // returns true Try it Yourself » Or even easier: Example (10 > 9) // also returns true 10 > 9 // also returns true Try it Yourself » For […]
Array Object The Array object is used to store multiple values in a single variable: var cars = [“Saab”, “Volvo”, “BMW”]; Array indexes are zero-based: The first element in the array is 0, the second is 1, and so on. For a tutorial about Arrays, read our JavaScript Array Tutorial. Array Properties Property Description constructor Returns the function that […]
Bold Object The Bold object represents an HTML <b> element. Access a Bold Object You can access a <b> element by using getElementById(): Example var x = document.getElementById(“myB”); Try it Yourself » Create a Bold Object You can create a <b> element by using the document.createElement() method: Example var x = document.createElement(“B”); Try it Yourself » Standard […]
Audio Object The Audio Object is new in HTML5. The Audio object represents an HTML <audio> element. Note: The <audio> element is not supported in Internet Explorer 8 and earlier versions. Access an Audio Object You can access an <audio> element by using getElementById(): Example var x = document.getElementById(“myAudio”); Try it Yourself » Create an Audio Object […]
Style object The Style object represents an individual style statement. Style Object Properties The “CSS” column indicates in which CSS version the property is defined (CSS1, CSS2, or CSS3). Property Description CSS alignContent Sets or returns the alignment between the lines inside a flexible container when the items do not use all available space 3 […]
