Javascript triangle project

So I'm trying to write a JS that takes the sides of triangles and determines if they're real or not. It keeps fucking up though and I have NO idea why.
Code:
//Gather input
var side1 = prompt("Input the length of side A(Not the longest).");
var side2 = prompt("Input the length of side B(Not the longest).");
var side3 = prompt("Input the length of side C(Longest side).");
//Create triangle object
var triangle = new Object();
//Find out if the triangle is real
real = function() {
if (side1 + side2 <= side3 || side2 + side1 <= side3) {
triangle.real = "not real";
}
else{
triangle.real = "real";
}
};
//Call functions and display answer
real();
alert("The triangle is " + triangle.real + ".");

prompt("Input the length of side A(Not the longest).")
prompt("Input the length of side B(Not the longest).")
prompt("Input the length of side C(Longest side).")
Why would you make the user deal with bullshit like this? This is bad behavior. What if multiple sides are the longest?

side1 + side2 <= side3 || side2 + side1 <= side3
...

triangle.real = "not real"
Bools?