Bouton Quantité

<input type="text" id="id_du input">

.spinbox {
	position:relative;
}

.spinbox input:last-child {
	position:absolute;
	right:0;
	width:22px;
	height:22px;
}

.spinbox input:nth-last-child(2){
	position:absolute;
	right:22px;
	width:22px;
	height:22px;
}

<script type="text/javascript">

$("#id_du input").spinbox();


(function($) {

	$.widget("ui.spinbox", {

		options: {},

		_create: function() {
			this.spinbox = $('<div class="spinbox"></div>').insertBefore(this.element);
			this.element.appendTo(this.spinbox);
			this.decrease = $('<input type="button" value="-">').appendTo(this.spinbox);
			this.increase = $('<input type="button" value="+">').appendTo(this.spinbox);

			var self = this;
			
			this.decrease.click(function(){
				var foo = ( parseInt( self.element.val() , 10 ) > 0 )? parseInt( self.element.val() , 10 ) -1 : 0 ;
				self.element.val( foo );
			});
			
			this.increase.click(function(){
				var foo = parseInt( self.element.val() , 10 ) +1 ;
				self.element.val( foo );
			});
		}
	});
		
	$.extend($.ui.spinbox, {
		locale: {
		}
	});

})(jQuery);

</script>