Here are some examples: true & false & true // returns false Last term otherwise (if all are true-y).However, in JavaScript, it is extended to allow any data type and any number of terms.

Most usually, programmers use this operator to check if both conditions are true, for example: true & true // returns true How does it work? Wikipedia has an answer: & is logical AND In case they are not numbers, they are cast to numbers. This operator expects two numbers and retuns a number. In JavaScript, it has questionable performance, and we rarely work with binary data. Other programming languages (like C and Java) use it for performance reasons or to work with binary data. The alternative solution is that we must have to specify the section just before the tag of HTML file.This operator is almost never used in JavaScript. The defer attribute is not allowed in older browsers, so for older browsers we have to use the alternative of the defer attribute.

So, by using the defer attribute, we can increase the loading performance. In mobile devices, it will be a worse situation because of the low memory of small devices.

Sometimes the script takes more than expected loading time and displays the blank page instead of content. To improve the performance, we can add the defer attribute in the tag. Sometimes, the application consumes more memory by adding the tag in the HTML head section, and it also causes performance issues. This attribute tells the browser to execute the file when the entire HTML document gets fully parsed. We can understand the use of the defer attribute in the following image: The with the defer attribute does not block the page. So, the browser can continue the parsing of the rest of the page. It declares that the script will not create any content. It works only with external scripts (i.e., works only when we are specifying the src attribute in tag). The defer is a Boolean value, used to indicate that script is executed after the document has been parsed.

What is mean in javascript