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Articles by Abhishek Kumar
14 articles
How to use an HTML button to call a JavaScript function?
We use the onclick event attribute property of the HTML button to call a JavaScript function. The JavaScript code provided in the onclick attribute executes when the button is clicked. There are various attributes provided with the button tag in HTML that allows us to customize the button’s functionality and also let us decide how and what the button triggers. Approach 1: Using the onclick event in JavaScript The onclick event of the button element expects JavaScript code that is triggered when the button is clicked upon. So we put the function that needs to be called in the onclick ...
Read MoreHow to use for...in statement to loop through an Array in JavaScript?
We use the for...in statement of JavaScript for looping over enumerable properties of an array or object. It is a variety of for loops. Unlike other loop constructs in JavaScript, the for...in loop doesn’t have to bother about the number of iterations. This is because the iteration size is fixed based on the enumerable properties of the object or the number of elements in the array. The "for...in" statement in JavaScript A for...in loop iterates over all the enumerable properties of an object. All the properties that are assigned using a simple assignment operator or by default initializer are considered ...
Read MoreHow to use 'const' keyword in JavaScript?
We use the const keyword in JavaScript to declare variables whose value can be initialized only at the time of declaration. It is similar functionality of declaring variables as the other keywords provided in JavaScript i.e. var and let. const is short for constant, meaning that the value that resides in the variable is unchangeable. The const keyword in JavaScript It is used to declare variables in JavaScript. The variables created using const follow certain rules. The variable is block scoped. This means that the scope(lifetime) of the variable depends on the place where it has been declared. This ...
Read MoreHow to use associative array/hashing in JavaScript?
We use Object and Map classes to mimic the behavior of associative array/hashing in JavaScript. JavaScript doesn’t provide an associative array built-in. The closest similar behavior we get is from the Map class in JavaScript. Let us look at them one by one. Object class in JavaScript The object class allows us to create objects with name-value pairs. This is similar to hashing as the object knows which property is associated with what value. Syntax const obj = { name : "Abhishek", age : 22 } var name = obj.name This creates an ...
Read MoreHow to use a line break in array values in JavaScript?
We use the join() method of JavaScript to use a line break in array values. It allows us to concatenate all the constituent elements of an array into a single string using a common separator. The join() method in JavaScript The join() method takes as input a single separator string and returns a string with all the elements of the array separated by the specified separator string. The separator string by default is the comma(, ). The join method uses the toString() method to convert the elements of the array into corresponding strings. A null or undefined value is converted ...
Read MoreHow to use Spread Syntax with arguments in JavaScript functions?
We use the Spread Syntax of JavaScript to expand an array, string, or object in place. Such types of values are called iterable. This is similar to destructuring the iterable in place. Its utility in a function call allows us to extract function parameters from an iterable. In this tutorial, we learn how to use Spread Syntax with arguments in JavaScript functions. Spread operator in JavaScript A Spread operator, denoted with (...) followed by the name of the iterable expands the iterable into its constituent elements. e.g. const [x, y, ...z] = [1, 2, 3, 4, 5] This creates ...
Read MoreHow to use JavaScript to show a confirm message?
In this tutorial, we will learn how to use JavaScript to show a confirm message. We use window.confirm() method of JavaScript to show a confirm message. A confirm message is enclosed in a confirm dialog box which is a modal window. Such a window takes focus upon being created and doesn’t go out of focus until the user responds to it. Confirmation dialog box in JavaScript A confirm message is a yes/no message for the user that requires immediate attention. A confirmation dialog box usually gets triggered in response to some action requested by the user. This action can be ...
Read MoreHow to use JavaScript to set cookies for a specific page only?
We can set cookies for a specific page only using JavaScript. We use the path attribute of the document.cookie property to set the cookie on a specific webpage. Cookies are small text files (4 KB) that store important information such as username, email, session id, and other preferences that help customize the webpage for a particular user. Something so trivial as this is a user preference and thus can be conveniently stored in a corresponding cookie file. The pathname property of the Window location returns a string containing the path of the current webpage. The path is basic information about ...
Read MoreHow to show the number of links in a document with JavaScript?
We use the links property of the document object to show the number of links in a document with JavaScript. The document object, part of the DOM, corresponds to the current web page that the browser has loaded. It Contains all the information about the condition of the browser as well as the web page. The links is a property of the document object that returns a list of all the hyperlinks present in the HTML document. A hyperlink may look something like this − "https://www.tutorialpoints.com/php" The links property of the document object lists all HTML elements having href ...
Read MoreHow to show the index of the selected option in a dropdown list with JavaScript?
We use the selectedIndex property in JavaScript to show the index of the selected option in a dropdown list. We use the id of the dropdown list to access the element using JavaScript and then call selectedIndex on it to get the index of the selected option in the dropdown list. Dropdown lists are an important part of user interface utility. It is a list of options from which one or multiple options can be selected by the user. These responses to these dropdown lists are then collected and the required course of action is taken by the user. A ...
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