safari=(navigator.userAgent.indexOf('Safari')!=-1);
function doPrevious() {
	if (document.images) {

		if (current > 0) {
			
			if (safari) {
				document.portfolioimg.src = "images/trans.gif" ;
			}
			document.portfolioimg.src = imgarr[current-1] ;
			current-- ;
		}
	}

	nav();
}


function doNext() {

	if (document.images) {

		if (current < numimages) {

			if (safari) {
				document.portfolioimg.src = "images/trans.gif" ;
			}
			
			document.portfolioimg.src = imgarr[current+1] ;
			current++ ;
		}
	}

	nav();

}

function doPreviousText() {
	if (document.images) {

		if (current > 0) {
			
			if (safari) {
				document.portfolioimg.src = "images/trans.gif" ;
			}
			
			document.portfolioimg.src = imgarr[current-1] ;
			document.getElementById('desctitle').innerHTML=titlearr[current-1] ;
			document.getElementById('descriptiontest').innerHTML=textarr[current-1] ;
			current-- ;
		}
	}

	nav();
}


function doNextText() {

	if (document.images) {

		if (current < numimages) {

			if (safari) {
				document.portfolioimg.src = "images/trans.gif" ;
			}
			current++;
			document.portfolioimg.src = imgarr[current] ;
			document.getElementById('desctitle').innerHTML=titlearr[current] ;
			document.getElementById('descriptiontest').innerHTML=textarr[current] ;
		}
	}

	nav();

}

function nav() {

	if (current > 0) {
		document.back.src = "mlab/back_left.gif";
	} else {
		document.back.src = "mlab/back_leftstart.gif";
	}

	if (current >= numimages) {
		document.next.src = "mlab/back_rightlast.gif";
	} else {
		document.next.src = "mlab/back_right.gif";
	}

}