var pret_montant = 0;
var pret_echeance = 0;
var pret_taux = 0;

function calcul_pret(){
	if(isNaN($('pret_montant').value)){$('pret_montant').style.border = "2px solid red"; return false;}
	else{$('pret_montant').style.border = "1px solid green";}
	if(isNaN($('pret_echeance').value)){$('pret_echeance').style.border = "2px solid red"; return false;}
	else{$('pret_echeance').style.border = "1px solid green";}
	
	$('pret_taux').value = $('pret_taux').value.replace(",", ".");
	if(isNaN($('pret_taux').value)){$('pret_taux').style.border = "2px solid red"; return false;}
	else{$('pret_taux').style.border = "1px solid green";}
	
	montant = $('pret_montant').value;
	echeance = $('pret_echeance').value;
	taux = $('pret_taux').value;
	
	pret_montant = montant;
	pret_echeance = echeance;
	pret_taux = taux;
	
	taux = parseFloat(taux/100)/12;
	mensualite = (montant * taux) / (1-(1/(Math.pow((1+taux),echeance))));
	mensualite = Math.floor(mensualite);
	cout_credit = (mensualite*echeance)-montant;
	
	$("boite_pret").innerHTML = "<h1>Simulateur de Pr&ecirc;t</h1>Capital : <strong>"+montant+" &euro;</strong><br />dur&eacute;e : <strong>"+echeance+" mois</strong><br /> taux : <strong>"+$('pret_taux').value+" %</strong> <br /><br /> Mensualit&eacute;s :<br /><span class='mensualite'>"+mensualite+" &euro;</span>co&ucirc;t du cr&eacute;dit : <br /><strong>"+cout_credit+" &euro;</strong><br /><input type='button' value='retour' class='ok' onclick='restore_pret();' /><div style='clear:both; height:1px;font-size:1px;'>&nbsp;</div>";
	
}

function restore_pret(){
	$("boite_pret").innerHTML = "<h1>Simulateur de Pr&ecirc;t</h1><input type='text' size=7 value='"+pret_montant+"' id='pret_montant' onfocus='this.value=\"\"' /> &euro; <input type='text' size=7 value='"+pret_echeance+"' id='pret_echeance' onfocus='this.value=\"\"' /> mois <input type='text' size=7 value='"+pret_taux+"' id='pret_taux' onfocus='this.value=\"\"' onkeypress='if(event && event.which == 13)calcul_pret();' /> %<input type='button' value='ok' class='ok' onclick='calcul_pret();' /><div style='clear:both; height:1px;font-size:1px;'>&nbsp;</div>";
}