Really stumped. What if the user provides a number lower than the first number chosen?

//Prompt for user to enter a random number
//Number is converted to an Integer if it isn't already
var userInput1 = prompt('Please think of a number and type it below.');
userInput1 = parseInt(userInput1);
console.log(userInput1);


//Prompt for user to enter a second random number
//Number is converted to an Integer if it isn't already
var userInput2 = prompt('Thank you. Now please select a different number at random and type it below.');
userInput2 = parseInt(userInput2);
console.log(userInput2);



//Message displayed declaring a random number is to be selected by the computer
alert('Now I will pick a random number between the two numbers you have selected.');
console.log('Alert displayed');

//function to figure out the lower number
function lowerSelector() {
  if (userInput1 < userInput2) {
    lowerNumber = userInput1;}
  else {
  lowerNumber = userInput2;}
}

//Function to figure out the higher number
function higherSelector() {
  if (userInput1 < userInput2) {
    higherNumber = userInput2;}
  else {
    higherNumber = userInput1;}
}


//Running the Functions
lowerSelector();
document.write('Lower Number: ' + lowerNumber + '<br/>');

higherSelector();
document.write('Higher Number: ' + higherNumber + '<br/>');


//Generating the random number within range provided
var result = Math.floor(Math.random() * (higherNumber - lowerNumber + 1)) + lowerNumber;
document.write('Your random number between the specified values is: ' + result + '!');
alert('Your number is ' + result + '!');