Variables and functions defined outside of a function have a global scope. The global scope in JavaScript is the widest possible scope. It exists across the entire web page, and all variables and functions created in the global scope can be used anywhere on the page. In addition to variables, functions can also have a global scope. These are functions defined in the code itself, not within another function. Global variables and functions exist throughout the entire page and remain relevant as long as the user does not navigate to another page. Besides the global scope, there is also the functional or...

isladjan

Created: 02/28/2019Comments:2Views: 22

In JavaScript, a function is treated as a value, meaning it can be used in place of any other value. A function can also be declared by assigning it to a variable, thereby giving the function the name of the variable it is assigned to. In other words, the variable becomes the function. These types of functions are called anonymous functions. However, we can also assign a name to such functions, which is useful when creating self-invoking functions. For these functions, a semicolon is required at the end. This method is used when the function is needed only once or when...

isladjan

Created: 02/28/2019Comments:0Views: 10

The latest API for monitoring Web Performance. It is slightly more complicated to set up, but the advantage is that it uses the same syntax as other Observer APIs (Resize Observer, Intersection Observer, and Mutation Observer). The Performance Observer API allows you to set up something similar to an event, which monitors specific configured web performance metrics and triggers a callback function when those results become available in the browser's performance timeline. Within the callback function, you can access this data. The Performance Observer API is used to monitor, test, or measure performance metrics to improve your application....

isladjan

Created: 02/28/2019Comments:0Views: 3

There are many APIs and techniques for measuring the performance of a web page (all the APIs listed below are interconnected, share similar syntax, and inherit properties from each other – most importantly, they are used in the same way): Performance API – Used to precisely measure the time required for specific performance evaluations. It contains other APIs, each of which measures a specific aspect of the web page's performance. All these APIs are used in the same way (explained in detail under the heading below: Performance APIs). Most...

isladjan

Created: 02/28/2019Comments:0Views: 3