Really need some feedback!

According to the random challenge, it requires the user to create a range between [a;b] with b>a and both of them are random visitor's inputed integers. So my question contains three parts:

• Is my below mathematical explanation for the question correct?

[a;b] = [0 + a; b -a +a] Math.random() -> [0;1) Math.random() * (b-a) -> [0;b-a) If I use the floor function and the result is this: Math.floor(Math.random() * (b-a)) -> [0; b-a-1] Wrong way to create (b - a) gap. If I use the ceil function and the result is this: Math.ceil(Math.random() * (b-a)) -> [0; b-a] Math.ceil(Math.random() * (b-a)) + a -> [a;b]

• Secondly, do you see anything wrong in my script written below?

var firstNumber = prompt("Please give me a number."); var secondNumber = prompt("Give me another number that\'s smaller than the first one."); var numberx = Math.ceil(Math.random() * (parseInt(firstNumber) - parseInt(secondNumber))) + parseInt(secondNumber); document.write(numberx);

• Finally, is there any function that is able to compare the margin between two inputed numbers regardless the order - either the smaller is first or second - of the visitor log in the prompt command? As you can see, my script would go wrong if the user enters the first value which is smaller than the second.

Any help is really appreciate about this matter.