Hello Friends,
Validating Credit Card Numbers Using JavaScript
Some times we accept money through credits.We nee dto validate the credit cards ..
This task illustrates how to validate a credit card number by the following logic:
• Check if the credit card number is empty; if it is, the field is not valid.
• Remove any spaces.
• Check the length of the credit card number; valid lengths are discussed
in this task. If the length is wrong, the field is not valid.
• Check for nonnumeric characters; if any occur, the field is not valid.
• Otherwise, the field is valid.
function checkCreditCard(card)
{
if (card.length == 0)
{
window.alert(“You must provide a credit card number.”);
return false;
}
card = card.replace(“ “,””);
if (card.substring(0,1) == “4”)
{
if (card.length != 13 && card.length != 16)
{
window.alert(“Not enough digits in Visa number.”);
return false;
}
} else if (card.substring(0,1) == “5” && (card.substring(1,2) >= “1” && card.substring(1,2) <= “5”))
{
if (card.length != 16) {
window.alert(“Not enough digits in MasterCard.”);
return false;
}
} else if (card.substring(0,1) == “3” && (card.substring(1,2) == “4” || card.substring(1,2) == “7”))
{
if (card.length != 15)
{
window.alert(“Not enough digits in American Expr.”);
return false;
}
}
else
{
window.alert(“This is not a valid card number.”);
return false;
}
for (i=0; i{
if (card.charAt(i) < “0” || card.charAt(i) > “9”)
{
window.alert(“CCard must only contain numbers.”);
return false;
}
}
return true;
}
Description:
We nee dto call this method from onchange of textbox or onclick of submit button
For example:
<form name=”myForm” action=”target.html”
onSubmit=”return checkForm(this);”>
Credit Card: <input type=”text” name=”myField”><br>
<input type=”submit”>
</form>
Thanks & Regards,
Datta.G.
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