div{
    width: 300px;
    height: 150px;
    border: 5px dashed #333;
    padding: 10px;
    margin: 10px auto;
    background-color : RGBa(255, 255, 255, 0.2);
}

/*Une déclaration en omettant des valeurs*/
#ex1{
    background: 
	url("../images/emoji-smile.png")
	/*posistion/size manquent*/
	repeat-x 
	/*att,origin,clip manquent*/
	RGBa(250,250,0,1); /*full opaque*/
}

/*Une déclaration complète*/
#ex2{
    background: 
	url("../images/emoji-smile.png") 
	top right / 50px auto 
	repeat-x 
	/*background-attachment manque*/
	padding-box 
	content-box 
	RGBa(250,250,0,0.2);
}
/*2 images de fond avec background*/
#ex3{
    background: 
	url("../images/emoji-smile.png") 
	top right 
	repeat-x 
	padding-box,
    url("../images/emoji-think.png") 
	bottom left no-repeat 
	RGBa(250,250,0,0.2);
}