//SOMME DES MONTANT TTC LIGNES ADD
function sum_montant(){
   var somme_montant = 0;
   var result = document.getElementById('somme_montant');
   for(var i = 1; i<=7; i++){
      var element = document.getElementById('montant_'+i);
      if(element.value!='' && !isNaN(element.value)){
         somme_montant += parseFloat(element.value);

      }
   }
   result.value = somme_montant;
}

//MULTIPLICATION DES LIGNES
function multi_1(){

	var pu_1 = +document.forms.form.pu_1.value;
	var qte_1 = +document.forms.form.qte_1.value;
	var total_1 = qte_1 * pu_1;

	document.getElementById('montant_1').value = total_1;
}