var iElementWidth = 164;
var iDisplayedElements = 4;
var iFirstElement = 1 ;
var iLastElement = 4 ;
var iSize;

window.onload = function() {
	iSize = getElementsByClassName('carousel_element', 'div', document.getElementById('carousel_elements')).length;
	$('carousel_elements').style.width = (iSize * iElementWidth) + 'px';
}

function slidePreviousElement() {
	
	$('previous_link').onclick = "return false;";
	
	if(iFirstElement > 1) {
		
		iDeplacement = 4;
		if(iFirstElement < 4) {
			iDeplacement = iFirstElement - 1;
		}
		
 		effect_scroll_selection = new Effect.Move($('carousel_elements'),{x:(164 * iDeplacement), y: -0, duration: 1, mode:'relative' })
	}
	
	iFirstElement = iFirstElement - iDeplacement ;
	iLastElement = iLastElement - iDeplacement ;
	
	if(iFirstElement == 1)
    	$('previous').style.visibility = 'hidden';
    	
    if(iLastElement < iSize)
    	$('next').style.visibility = 'visible';
    	
    setTimeout('activePreviousButton()', 1000);
    
}


function slideNextElement() {
	
	$('next_link').onclick = "return false;";
	
	if(iLastElement < iSize) {
		
		iDeplacement = 4;
		iElementsRestants = iSize - iLastElement;
		if(iElementsRestants < 4) {
			iDeplacement = iElementsRestants;
		}
		
		effect_scroll_selection = new Effect.Move($('carousel_elements'),{x:(-164 * iDeplacement), y: -0, duration: 1, mode:'relative'})
	}
		
	iFirstElement = iFirstElement + iDeplacement ;
	iLastElement = iLastElement + iDeplacement ;
	
	if(iFirstElement > 1)
    	$('previous').style.visibility = 'visible';
    
    if(iLastElement == iSize)
    	$('next').style.visibility = 'hidden';
    
    setTimeout('activeNextButton()', 1000);
    
}


function activePreviousButton() {
	$('previous_link').onclick = function() {slidePreviousElement(); return false;};
}


function activeNextButton() {
	$('next_link').onclick = function() {slideNextElement(); return false;};
}