Javascript Articles - Page 583 of 607

To use OR condition in JavaScript IF statement, use the || operator i.e Logical OR operator. If any of the two operands are non-zero, then the condition becomes true.Here’s how you can use the operator || in JavaScriptExampleLive Demo                    var a = true;          var b = false;          document.write("(a || b) => ");          result = (a || b);          document.write(result);          

The for each...in loop iterates a variable overall value of the properties of objects. Note − The “for…each..in” is now deprecated. Do not use. SyntaxHere’s the syntax −for each (variablename in object) {    statement or block to execute }ExampleHere’s an example, which will not run on any of the web browsers, since “for each..in” is now deprecated −                    var myObj = {myProp1:30, myProp2: 40};          var sum = 0;          for each (var value in myObj) {             sum += value;          }          document.write(sum);          

It’s not possible to edit a JavaScript alert box title due to security issues. Still, to edit an alert box to work it all web browsers, use custom JavaScript Modal Dialogs or jQuery plugins.You can also use a custom alert box like Sweet Alert to get a custom alert box, with a title of your choice:

To create a custom object in JavaScript, try the following codeExampleLive Demo                          var dept = new Object();          dept.employee = "Amit";          dept.department = "Technical";          dept.technology ="Java";          document.getElementById("test").innerHTML =          dept.employee + " is working on " + dept.technology + " technology.";          

Use the super() function to call the constructor of the parent class and access functions on an object's parent class.ExampleYou can try to run the following code to implement super()Live Demo                    class Department {             constructor() {}             static msg() {                return 'Hello';             }          }          class Employee extends Department {             constructor() {}             static displayMsg() {                return super.msg() + ' World!';             }          }          document.write(Employee.displayMsg());          

The onsubmit event occurs when you try to submit a form. You can put your form validation against this event type. The following example shows how to use onsubmit. Here we are calling a validate() function before submitting a form data to the webserver. If validate() function returns true, the form will be submitted, otherwise it will not submit the data.     The HTML code snippet. …

The +function() {} notation is primarily used to force the parser to treat whatever follows the + as an expression. This is used for functions that are invoked immediately, for example,+function() { alert("Demo!"); }();However, + before a function is one of the symbol. You can add other options also like !, -, ~, also. Parentheses can also be used as shown below:(function() { alert("Demo!"); })();You can also use it like this:(function() { alert("Demo!"); }());

To add a new line in JavaScript alert box, use the “”:alert("Line One Line Two");ExampleYou can try to run the following code add a new line in an alert box in JavaScript:Live Demo                                         Click the following button to see the result:                          

The onmouseout triggers when you move your mouse out from that element.ExampleYou can try to run the following example to learn how to call a JavaScript function from onmouseout eventLive Demo                                         Bring your mouse inside the division to see the result:                 This is inside the division          

The onmouseover event triggers when you bring your mouse over any element.ExampleYou can try to run the following example to learn how to call a JavaScript function from onmouseover eventLive Demo                                         Bring your mouse inside the division to see the result:                 This is inside the division