Code next/previous buttons to choose items in a Javascript array in Adobe Edge

Question

I have an array of information I need to display in a function called updateMyInfo, which accepts an argument of the current index number. I start displaying the items at index 0, and there is a next/previous button to move through the array. So,I try:

// make the function visible anywhere
updateMyInfo = updateInfo;

function updateInfo(index) {
  slide.$("title").html(mySlide[index].title);
  slide.$("info").html(mySlide[index].info);
  slide.$("img").attr("src", "images/" + mySlide[index].img);
 }

var next = sym.getSymbol('details').getSymbolElement('next');
index = 0;
updateMyInfo(0);

next.click(function(){
    index++;
    updateMyInfo(index);    
});

The function is called once with index=0, great. I click next, index is 1 and second data shows. I click next again and index is 0 again.