//renvois de la hauteur de la fenetre
function getWindowHeight() {
    var windowHeight=0;
    if (typeof(window.innerHeight)=='number') {
        windowHeight=window.innerHeight;
    }
    else {
     if (document.documentElement&&
       document.documentElement.clientHeight) {
         windowHeight = document.documentElement.clientHeight;
    }
    else {
     if (document.body&&document.body.clientHeight) {
         windowHeight=document.body.clientHeight;
      }
     }
    }
    return windowHeight;
}
//renvois de la largeur de la fenetre

function getWindowWidth() {
    var windowWidth=0;
    if (typeof(window.innerWidth)=='number') {
        windowWidth=window.innerWidth;
    }
    else {
     if (document.documentElement&&
       document.documentElement.clientWidth) {
         windowWidth = document.documentElement.clientWidth;
    }
    else {
     if (document.body&&document.body.clientWidth) {
         windowWidth=document.body.clientWidth;
      }
     }
    }
    return windowWidth;
}




function positionne_element (evt, element_positionned) {
		var element = Event.element(evt);
    var offsets = Position.positionedOffset(element);
    var top     = offsets[1];
    var left    = offsets[0];
		//$(element_positionned).style.position="relative";
		$(element_positionned).style.top = top-200 +"px";
		//$(element_positionned).style.left = left+"px";
}

function return_width_element(id_element) {
	if($(id_element)) {
		var dimensions = $(id_element).getDimensions(); 
		return dimensions.width; 
	}
}

function return_height_element(id_element) {
	if($(id_element)) {
		var dimensions = $(id_element).getDimensions(); 
		return dimensions.height; 
	}
}


function centrage_element(id_element){
	if($(id_element)) {
		$(id_element).style.top = ( getWindowHeight()-return_height_element(id_element))/2+"px";
		$(id_element).style.left = (getWindowWidth()-return_width_element(id_element))/2+"px";
	}
}