Calling functions and getting an error that this is not a function in JavaScript

Question

In my second JavaScript class, I have not yet studied the bebugging tools, I look for errors that throw themselves into the browser. I have the following code (it includes data validation):

/**
* displayFunction gets info from form and displays message on screen
* it also called all the validation functions for the form
*/

function displayInfo() {
    //declare variables and initialize them.
    var fullName = document.myForm.fullName.value;
    var int1 = parseInt(document.forms["myForm"]["int1"].value);
    var int2 = parseInt(document.myForm.int2.value);
    var num3 = parseInt(document.myForm.num3.value);
    var num4 = parseInt(document.myForm.num4.value);
    var num5 = parseInt(document.myForm.num5.value);

    //make sure variable flag = 0
    flag = 0;
    //call the Validation functions
    nameValidate(fullName);
    int1Validate(int1);
    int2Validate(int2);
    num3Validate(num3);
    num4Validate(num4);
    num5Validate(num5);

    //call tha functions to find largest and smallest numbers and the sum
    var largest = largest(int1, int2, num3, num4, num5);
    var smallest = smallest(int1, int2, num3, num4, num5);
    var sum = sum(int1, int2, num3, num4, num5);

    //Display the outpu t it everything is entered right.
    if (flag == 1) {
        return false;
    } else {
        document.getElementById("message").innerHTML = "Hello, " + fullName + ". You entered: " + int1 + ", " + int2 + ", " + num3 +
        ", " + num4 + ", " + num5 + ". The largest number entered was " + largest + ". The smallest number you entered was " + smallest + 
        ". And the sum of all of the numbers was " + sum + ".";
    }
}

I try to take numbers from a form and then find the largest number, the smallest number and the sum. I made separate functions for them, and they are called in the code above, but, obviously, I miss some huge thing, because the check window in the browser throws an error that the “largest”, “smallest” and “sum” are not are functions. They are in code. I am trying to do this with an allergy headache, and I will miss something really small, I hope someone can determine what I do not see.

, :

/**
* largest takes in the numbers and returns the largest number
* @params - 5 ints
* @return - largest number
*/

//declare function largest and take in int1, int2, num3, num4, and num5
function largest (n1, n2, n3, n4, n5) {
    //declare variable largest and use Math.max to find the largest number
    var largest = Math.max(n1, n2, n3, n4, n5);

    return largest;
}

Answer 1

, , , . var , :

function displayInfo() {
  var largest;
  var smallest;
  var sum;
  // ...
  largest = largest(int1, int2, num3, num4, num5);
  smallest = smallest(int1, int2, num3, num4, num5);
  sum = sum(int1, int2, num3, num4, num5);

, largest, , largest, . ,

function largest() {
}
function doSomething() {
  console.log(typeof largest);
  var largest = largest();
}
doSomething();

:

var largestResult = largest(int1, int2, num3, num4, num5);
var smallestResult = smallest(int1, int2, num3, num4, num5);
var sumResult = sum(int1, int2, num3, num4, num5);