//Changement d'image avec fondu, en superposition avec une autre image => deux images dans le html, dont l'une placée sur l'autre, en position relative de la hauteur de l'image.

var repertoire		= '/imgs/';
var nbre_photos		= 4;

var change_image	= 15000; // temps entre chaque changement d'image
var temps_fondu		= 50 ; // temps entre chaque changement d'opacité => temps total : temps_fondu * coef * 100

var timer			= 0;

var sens = 0;
var coef = 0.02 ; // avancement de l'opacité

var test = 0;

/*****************************************************************************************************************/

var agt			= navigator.userAgent.toLowerCase();

var is_opera	= (agt.indexOf("opera") != -1);	
var is_mac		= (agt.indexOf("mac")!=-1);
var is_konq		= (agt.indexOf('konqueror') != -1);
var is_safari	= ((agt.indexOf('safari')!=-1)
					&&(agt.indexOf('mac')!=-1))?true:false;
var is_khtml	= (is_safari || is_konq);
var is_gecko	= ((!is_khtml)&&(navigator.product)
					&&(navigator.product.toLowerCase()=="gecko"))?true:false;
var is_fb		= ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1)	&&
					(agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)	&&
					(agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)		&&
					(is_gecko) && (navigator.vendor=="Firebird"));
var is_fx		= ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1)	&&
					(agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)	&&
					(agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)		&&
					(is_gecko) && ((navigator.vendor=="Firefox")||(agt.indexOf('firefox')!=-1)));
var is_moz		= ((agt.indexOf('mozilla/5')!=-1) && (agt.indexOf('spoofer')==-1)	&&
					(agt.indexOf('compatible')==-1) && (agt.indexOf('opera')==-1)	&&
					(agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)		&&
					(is_gecko) && (!is_fb) && (!is_fx) &&
					((navigator.vendor=="")||(navigator.vendor=="Mozilla")||(navigator.vendor=="Debian")));
var is_nav		= ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
					&& (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
					&& (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)
					&& (!is_khtml) && (!(is_moz)) && (!is_fb) && (!is_fx));
var is_ie6		= ((agt.indexOf('msie 6') != -1) && (!is_opera) && (!is_khtml));
var is_ie7		= ((agt.indexOf('msie 7') != -1) && (!is_opera) && (!is_khtml));
	
/*****************************************************************************************************************/

function onLoad() {
	
	if (!is_ie6) {
		window.setInterval(function() { change(); }, change_image);
	} else {
		//document.getElementById('imageTopHomeAsc').style.top = "-95px";
	}

}
	
function change() {
	
	if( sens == 0 ) {
		var id1 = 'imageTopHomeDesc';
		var id2 = 'imageTopHomeAsc';
	} else if( sens == 1) {
		var id1 = 'imageTopHomeAsc';
		var id2 = 'imageTopHomeDesc';
	}
	
	timer	= window.setInterval("change_opacity('"+id1+"', '"+id2+"')",temps_fondu);
	
}

function change_opacity(idDesc, idAsc) {
	
	var imageDesc	= document.getElementById(idDesc);
	var imageAsc	= document.getElementById(idAsc);
	
	if (is_ie7) {
		opacityDesc	= parseFloat(imageDesc.filters.alpha.opacity);
		
		opacityAsc	= parseFloat(imageAsc.filters.alpha.opacity);
	} else if( (is_fx) || (is_moz) ) {
		opacityDesc	= parseFloat(imageDesc.style.MozOpacity);
		
		opacityAsc	= parseFloat(imageAsc.style.MozOpacity);
	} else if(is_safari) {
		opacityDesc	= parseFloat(imageDesc.style.opacity);
		
		opacityAsc	= parseFloat(imageAsc.style.opacity);
	}
	
	var opacityDesc_saved = opacityDesc;
	var opacityAsc_saved = opacityAsc;
	
	if (is_ie7) {
		opacityDesc -= coef * 100;
		imageDesc.filters.alpha.opacity	= opacityDesc;
		
		opacityAsc += coef * 100;
		imageAsc.filters.alpha.opacity	= opacityAsc;
	} else if( (is_fx) || (is_moz) ) {
		opacityDesc -= coef;
		imageDesc.style.MozOpacity	= opacityDesc;
		
		opacityAsc += coef;
		imageAsc.style.MozOpacity	= opacityAsc;
	} else if(is_safari) {
		opacityDesc -= coef;
		imageDesc.style.opacity		= opacityDesc;
		
		opacityAsc += coef;
		imageAsc.style.opacity		= opacityAsc;
	}
	
	if( opacityDesc==0 ) {
		
		var nber = Math.round((Math.random()*(nbre_photos-1))+1);
		imageDesc.src= repertoire+'top'+nber+'.jpg';
		
		if (is_ie7) {
			imageDesc.filters.alpha.opacity = 0;
		} else if( (is_fx) || (is_moz) ) {
			imageDesc.style.MozOpacity	= 0;
		} else if(is_safari) {
			imageDesc.style.opacity		= 0;
		}
		
	}
	
	if( (opacityAsc==1) || (opacityAsc==100) ) {
		
		if (is_ie7) {
			imageAsc.filters.alpha.opacity = 100;
		} else if( (is_fx) || (is_moz) ) {
			imageAsc.style.MozOpacity	= 1;
		} else if(is_safari) {
			imageAsc.style.opacity		= 1;
		}
		
		(sens) ? sens = 0 : sens = 1 ;
		clearInterval(timer);
	}

}