GUID - not actual GUID but create number the looks like a GUID. Good for simple id extensions or in scorm pkg
function s4() {
return Math.floor((1 + Math.random()) * 0x10000)
.toString(16)
.substring(1);
}
function guid() {
return s4() + s4() + '-' + s4() + '-' + s4() + '-' +
s4() + '-' + s4() + s4() + s4();
}