Move jQuery to the end of body tag?

Question

My friend read an article which mentioned that moving all JavaScript files to the end of the closing body tag (), will improve the performance of a

Answer 1

Q - Why do I often see JavaScript written/included before the closing body element in an (x)HTML document?

A - DOM elements can not be accessed by JavaScript until the browser has loaded the HTML elements into the DOM. By placing JavaScript at the end of an (x)HTML document (before the closing body element), you will ensure that the script is called as soon as the DOM is constructed/loaded and ready for manipulation. An advantage of this approach is that JavaScript code is executed right after the DOM is constructed and possibly before the onload event would fire.

JavaScript beginners get tripped up by this constantly by placing code that manipulates the DOM in the header element of an (x)HTML document. This causes an error because the DOM has not yet been constructed and thus is not yet accessible to JavaScript that traverses/manipulates the DOM.

From JavaScript Execution & Onload Techniques in Web Browsers