console.log(uuid()); console.log(uuid()); console.log(uuid()); console.log(uuid()); function uuid() { var code = 'abcdef1234567890'; var max = code.length; var str = ''; for (var i=0; i<32; i++) { str += code.charAt(Math.floor(Math.random() * max)); if (i==8 || i==12 || i==16 || i==20 ) { str += '-'; } } return str; }