function changeHref(hrefElement, hreftext, imgElement, imgtext){
    document.getElementById(imgElement).innerHTML = imgtext;
    document.getElementById(imgElement).title=imgtext;
}
function changeText(currentElement, imgtext){
    document.getElementById(currentElement).innerHTML = imgtext;
    document.getElementById(currentElement).title=imgtext;
}

var i=0;
var j=0;
var maxj=0;
var portfolioImages=new Array();

function nxt_portfolio_image () {
  j++;
  if (j>maxj) {j=0;}
  document.images.portfolio.src = portfolioImages[j];
}
function prev_portfolio_image () {
  j--;
  if (j<0) {j=maxj;}
  document.images.portfolio.src = portfolioImages[j];
}
function handleArrowKeys(evt) {
    evt = (evt) ? evt : ((window.event) ? event : null);
    if (evt) {
        switch (evt.keyCode) {
            case 37:
                prev_portfolio_image();
                break;    
            case 38:
                prev_portfolio_image();
                break;    
            case 39:
                nxt_portfolio_image();
                break;    
            case 40:
                nxt_portfolio_image();
                break;    
         }
    }
}
document.onkeyup = handleArrowKeys;