What is wrong with my code?

i'm running into a problem in the JavaScript Basics course with the following task:

Create a new function named max which accepts two numbers as arguments (you can name the arguments, whatever you would like). The function should return the larger of the two numbers. HINT: You'll need to use a conditional statement to test the 2 parameters to see which is the larger of the two.

(task can be found here: https://teamtreehouse.com/library/javascript-basics/creating-reusable-code-with-functions/create-a-max-function )

Here is my code:

function max(value1, value2) {
    value1 = 6
      value2 = 8

  if (value1 > value2) {
        return value1;
  } else if (value2 > value1) {
        return value2;
  }
}

it worked perfectly fine when i tried in the dev tools console but for some reason when i check my work it says: Bummer: The max function doesn't seem to work. It should return the larger of the two numbers.