function calcul_art4(){
		var tr_a4 = Number(document.getElementById("trdeprix_a4").value);
			if (tr_a4==1) {
				var p1_a4 = Number(document.getElementById("p1_a4").value);
				var q_a4 = Number(document.getElementById("q_a4").value);
					if (q_a4>=1) {
						var p_a4 = Number(p1_a4);
						var total_a4 = Number(p_a4 * q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
				}
			else if (tr_a4==2) {
				var s1_a4 = Number(document.getElementById("seuilp1_a4").value);
                var p1_a4 = Number(document.getElementById("p1_a4").value);
				var p2_a4 = Number(document.getElementById("p2_a4").value);
                var q_a4 = Number(document.getElementById("q_a4").value);
					if (q_a4>=0 && q_a4<s1_a4) {
						var p_a4 = Number(p1_a4);
						var total_a4 = Number(p_a4 * q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
					else {
						var p_a4 = Number(p2_a4);
						var total_a4 = Number(p_a4* q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
				}
			else if (tr_a4==3) {
				var s1_a4 = Number(document.getElementById("seuilp1_a4").value);
				var s2_a4 = Number(document.getElementById("seuilp2_a4").value);
                var p1_a4 = Number(document.getElementById("p1_a4").value);
				var p2_a4 = Number(document.getElementById("p2_a4").value);
				var p3_a4 = Number(document.getElementById("p3_a4").value);
                var q_a4 = Number(document.getElementById("q_a4").value);
					if (q_a4>=0 && q_a4<s1_a4) {
						var p_a4 = Number(p1_a4);
						var total_a4 = Number(p_a4 * q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
					else if (q_a4>=s1_a4 && q_a4<s2_a4) {
						var p_a4 = Number(p2_a4);
						var total_a4 = Number(p_a4 * q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
					else {
						var p_a4 = Number(p3_a4);
						var total_a4 = Number(p_a4 * q_a4);
						document.getElementById("total_a4").value = total_a4.toFixed(2);
						var ttc_a4 = Number(total_a4 * 1.196);
						document.getElementById("ttc_a4").value = ttc_a4.toFixed(2);
						}
				}
    }