How can I get a substring located between 2 quotes?

If you want to avoid regular expressions then you can use .split("'") to split the string at single quotes , then use jquery.map() to return just the odd indexed substrings, ie. an array of all single-quoted substrings.

var str = "the word you need is 'hello'";
var singleQuoted = $.map(str.split("'"), function(substr, i) {
   return (i % 2) ? substr : null;
});

DEMO

CAUTION

This and other methods will get it wrong if one or more apostrophes (same as single quote) appear in the original string.