Javascript tax calculator need help to make sure its currency

Hi,

I made javascript code to calculate land transfer taxes. Basically the rules are:

• Transaction under 5000$ = no tax
  
• Transaction till 50000$ = 0,5% tax
  
• Transaction upto 250000$ = 0,5% for first 50000$, rest is 1,0%
  
• Transaction upto 500000$ = 0,5% for first 50000$, 1,0% for next 200000$ and 1,5% for everything over 250000$

I made this script:

function calculerTaxeDeBienvenue(){
	
	var montant = document.getElementById("valeur").value;
	montant = montant.replace(' ', '', 'g');
	montant = montant.replace(',', '', 'g');
	var resultat = 0;
	
	pageTracker._trackPageview('/taxedebienvenue/'+montant);
	
	montant = parseInt(montant);
	
	if (montant<5000){
	tropbas = "Il n'y aura pas de droits de mutation, or la ville pourrait charger un frais d'administration de 200,00$ maximum."
	document.getElementById("resultat").innerHTML = tropbas;
	}
	
	else {
	
	tranche3 = montant - 250000;
	if(tranche3>0) {
		resultat += (tranche3*1.5/100);
		montant -= tranche3;
	}
	
	tranche2 = montant - 50000;
	if(tranche2>0) {
		resultat += (tranche2*1.0/100);
		montant -= tranche2;
	}
	
	tranche1 = montant;
	if(tranche1>0) {
		resultat += (tranche1*0.5/100);
		montant -= tranche1;
	}
	
	document.getElementById("resultat").innerHTML = resultat+ "$, sera le montant de droit de mutation.";
	}
}

Code (markup):

However,

I dont know how ensure that people are entering amounts in dollars with either a comma or a dot as a separator for decimal, and that the tax will be calculated accordingly. Any help ?

 

Your code might be better if you use:

montant = montant.replace(/\s/g, '');
montant = montant.replace(/\$/g, '');
montant = montant.replace(/,/g, '.');

Code (markup):

so that the code is cross-browser compatible, all spaces and $'s are removed, and the commas are replaced with decimal points/periods so that you can re-use the code elsewhere. From there, you can test to make sure that the variable contains only numbers and decimal point/periods.