Strings have their own built-in variables and functions, also known as properties and methods. Here are some of the most common ones.
A string’s length property keeps track of how many characters it has.
A string’s toUpperCase method returns a copy of the string with its letters converted to capitals. Numbers, symbols, and other characters are not affected.
A string’s trim method returns a copy of the string with beginning and ending whitespace characters removed.
" but keep the middle spaces ".trim();
"but keep the middle spaces"