My if statement gives me the wrong output

Question

window.onload = start;


function start() {

  document.getElementById("kalk").onclick = find;
  find(1, 9999);
}

function find(min, max) {
  var factor = document.getElementById("tall").value;
  var factor2 = document.getElementById("tall2").value;

  var x = factor * factor2;

  document.getElementById("utskrift").innerHTML = x;

  if (x >= min && x <= max) {
    document.getElementById("msg").innerHTML = "Number is in interval."
  } else {
    document.getElementById("msg").innerHTML = "Number is not in interval."
  }
}

Gang to tall

T1  T2 

 Sum:

So by reading this code.. what Im trying to do is have two inputs where i multiply the numbers typed in them. In my "Find()" Parameter i have two arguments that says the numbers should be between 1-9999. In my "function find" i called these arguments min and max. Further down the code Im asking if the output is between these numbers are between min and max give "Number is in interval". The problem is that when i even when the numbers are in these arguments i get my else statement. Is there anyway to fix this or put an input felt in the parameter?

Thanks

user_9867451 · Answer

You are attaching the function find directly to the click event listener. The function is expecting two parameters min and max:

function find(min, max)

But when a click happens, it recieves, being an event listener, only one parameter which is the event object. Thus min is going to be an event object, and max will be undefined and your if statement won't work. You can check this out by logging min and max inside find to the console.

Wrap the function find call in another function and attach the latter as the event listener:

document.getElementById("kalk").onclick = function(event) { // the event listener function recieves the event object as the only parameter (not that argument event here is not necessary, I just added it for explanation)
   find(1, 90000);                                          // when this function get executed (when a click happens) then call find with proper parameters
}

user_695364 · Answer

Well, first you have to remember that the "T" in HTML stands for "text". There is only one data type in HTML... strings. When you get a value from HTML and want to use it as a number in JavaScript, you have to convert it to a number.

Next, you don't really have your functions organized correctly. find shouldn't just run as soon as the page is loaded. You want it to run when the button is clicked. And that way, the min and max values are passed at the moment you need them.

Lastly, you HTML statically says "Sum" when, you are in fact calculating a product.

See other best practice items in the comments.








  Gang to tall

T1 
T2 



Product:

My if statement gives me the wrong output

2 Answers