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JavaScript JavaScript Basics (Retired) Creating Reusable Code with Functions Random Number Challenge, Part II

Daniel Campbell
Daniel Campbell
10,148 Points
Posted by Daniel Campbell
Daniel Campbell
10,148 Points

random number is out of range

var lower = prompt("enter lower limit");
var upper = prompt("enter upper limit");

function getRandomNumber(lower, upper) {
  return Math.floor(Math.random() * (upper - lower + 1)) + lower; 
}

alert(getRandomNumber(lower, upper));

Hi, I'm getting numbers out of range and can't seem to figure it out.

2 Answers

Cheo R
Cheo R
37,150 Points
Cheo R
Cheo R
37,150 Points

Hello Daniel, you're on the right track. Remember that prompt() takes in a string, so you just need to convert the input with parseInt().

var lower = parseInt(prompt("enter lower limit"));
var upper = parseInt(prompt("enter upper limit"));

function getRandomNumber(lower, upper) {
 // document.write("Lower: " + typeof lower);
  return Math.floor(Math.random() * (upper - lower + 1)) + lower; 
}

alert(getRandomNumber(lower, upper));
Daniel Campbell
Daniel Campbell
10,148 Points
Daniel Campbell
Daniel Campbell
10,148 Points

Hi Cheo,

Thank you. It works! I tested to see if the prompt input was a number before using it in the function.

if ( isNaN(lower) || isNaN(upper)) {
throw new Error('oops');
}

I read that if an Integer is input in the prompt it doesn't need to be converted. I guess that's not true.