random string of letters javascript code example

Example: js random string

function randomString(length) {
		var result           = '';
		var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789~!@#$%^&*()_+=-';
		var charactersLength = characters.length;
		for ( var i = 0; i < length; i++ ) {
		   result += characters.charAt(Math.floor(Math.random() * charactersLength));
		}
		return result;
	 }
randomString(4);