var color="red";

showItem(color);

function showItem(item) {
  console.log(item);
}




multiple arguments
-----------------------------
var word = "hello";
var animals = ["cat", "dog", "bird"];

greeter(word, animals);

function greeter(str, arr) {
  var counter;
  for(counter = 0; counter < arr.length; counter++) {
    console.log(str + " " + arr[counter]);
  }
}

result:
"hello cat"
"hello dog"
"hello bird"