There's not really any way to know. Because of WordPress, PHP is still by far the most popular back-end language for the web (in terms of raw number of sites running on it).
Because JavaScript is the only language that runs in all browsers, it's by far the most widely-known language. Anyone who touches the web, which is most developers, tends to have at least a passing knowledge of it.
Because JavaScript is the only language that runs in all browsers, it's by far the most widely-known language. Anyone who touches the web, which is most developers, tends to have at least a passing knowledge of it.