How to check if variables are integer

JavaScript
1

Hi,

I have the following Javascript code to make a simple calculation. It works fine the numbers entered are integer. But if the numbers are 1.5 style I get stupid results or NAN error.

I would like to add a check to the script which checks:

1- If the value entered is integer or 1.5 style for all fields. If it is not gives an alert message and stop calculating.

2- If the visitor enters 1,5 instead of 1.5 (In Turkey it is a common usage.) I need script replace the 1,5 with 1.5 and then make the calculation.

Thank you in advance
telmessos


<html>
<head>
 <script type="text/javascript">
        function Hesapla() {
		kredimiktari = parseInt(document.hesapla.miktar.value);
                kredivadesi = parseInt(document.hesapla.vade.value);
		faiz = parseInt(document.hesapla.faiz.value);
		yuzdefaiz = faiz / 100;
		ayliktaksit1 = ((kredimiktari * yuzdefaiz) + kredimiktari) / kredivadesi;
		geriodeme1 = ((kredimiktari * yuzdefaiz) + kredimiktari);
		document.getElementById('ayliktaksit').innerHTML = "<strong>Taksit / Ay :</strong>" + ayliktaksit1;
		document.getElementById('geriodeme').innerHTML = "<strong>Toplam Geri Ödeme :</strong>" + geriodeme1;
        }
    </script>
</head>
<body>
<form name="hesapla">
                            
	<input type="text" name="miktar" value="Kredi Miktar&#305;" onfocus = "if (this.value == 'Kredi Miktar&#305;') this.value = '';"  onblur = "if (this.value == '') this.value = 'Kredi Miktar&#305;';" />
                           
	<input type="text" name="vade" value="Kredi Vadesi" onfocus = "if (this.value == 'Kredi Vadesi') this.value = '';"  onblur = "if (this.value == '') this.value = 'Kredi Vadesi';" />
                            
	<input type="text" name="faiz" value="Faiz Oran&#305;" onfocus = "if (this.value == 'Faiz Oran&#305;') this.value = '';"  onblur = "if (this.value == '') this.value = 'Faiz Oran&#305;';" />
                            
<div id="gosterim"><span id="ayliktaksit"></span><span id="geriodeme"></span></div>
                            
<input type='button' value='Hesapla' onClick='Hesapla()'><br><br>
<img src="http://www.sitepoint.com/forums/images/dot2.png" width="180" height="2" alt="dot"/>
                        
</form>
</body>
</html>

The parseint functions seems to delete the part after the . but I don’t know how to fix the problem

2

Those can be done in reverse order. You can replace any commas with full stops, with string.replace(‘,’, ‘.’)

Then, you can use parseFloat(string) to retrieve a numeric version of the string, and use isNaN to check if it’s a valid number or not.

3

Many thanks,

The working code is below:


 function Hesapla() {
        //use var statement to localize variables
        var yuzdefaiz, ayliktaksiti, geriodeme1,
            //since I assume you want to allow floating point numbers (1.5 style) or integers
            //use the Number constructor function to try and convert numeric string to Number
            //oh yeah, plus a replace of ',' with '.'
            kredimiktari = Number(document.hesapla.miktar.value.replace(/,/, '.')),
            kredivadesi = Number(document.hesapla.vade.value.replace(/,/, '.')),
            faiz = Number(document.hesapla.faiz.value.replace(/,/, '.'));
        //check for valid numbers
        if (isNaN(kredimiktari) || isNaN(kredivadesi) || isNaN(faiz)) {
            alert('Giris, Geçersiz!');
        }
        yuzdefaiz = faiz / 100;
        ayliktaksit1 = ((kredimiktari * yuzdefaiz) + kredimiktari) / kredivadesi;
        geriodeme1 = ((kredimiktari * yuzdefaiz) + kredimiktari);
        document.getElementById('ayliktaksit').innerHTML = "<strong>Taksit / Ay :</strong>" + ayliktaksit1;
        document.getElementById('geriodeme').innerHTML = "<strong>Toplam Geri Ödeme :</strong>" + geriodeme1;
    }