generateHTML vs generateHTML()

Eddie Lam I will try to explain this as best I can.

with your function getJason it expects certain values.

getJason(url, callback)

so if you pass in generateHTML() what you are doing is you are running the function and trying to pass whatever it returns in. If it has no return it will pass "undefined" . so what you actually end up with is

getJason(url, undefined){
// some code here
undefined(data)
}

when you pass in generateHTML you are passing a reference to the generateHTML() function. so now it looks like this

getJason(url, generateHTML){
// some code here
generateHTML(data)
}

To sum up if you have () at the end you are invoking the function and passing whatever it returns into the expected value. so your value here wouldnt work. expected value !== passed in value.

hope this makes more sense. If this resolved your question please select best answer to mark it resolved.