Validation

[bldstr]

I have a form which checks the user input is a valid UK post code, if ithe postcode isn't valid a Javascript pop-up appears. However, the post code is optional so if the input box is blank I would like like to bypass the validation.

The form code is:

<input type="text" id="postcode" maxlength="13" size="13" style="margin-left: 10px;" alt="Enter test postcode" />

The JavaScript in the head is:

function testPostCode () {
  var myPostCode = document.getElementById('postcode').value;
  
  if (checkPostCode (myPostCode)) {
    document.getElementById('postcode').value = checkPostCode (myPostCode)
    return flase;
  } 
  else {alert ("Postcode has invalid format")};
}

"checkPostCode" is the function that performs the actual validation on the post code, I don't think it's necessary to list it here as it is very large and I'd like to bypass it anyway if the field is blank.

Thanks

[Selrach]

function testPostCode () {
  var myPostCode = document.getElementById('postcode').value;
  if(myPostCode == '') return false;
  if (checkPostCode (myPostCode)) {
    document.getElementById('postcode').value = checkPostCode (myPostCode)
    return false;
  } 
  else {alert ("Postcode has invalid format")};
}

[bldstr]

Thank you, very much appreciated.

I wonder if you could help me with the other thing I'm not sure of? This form goes to another page when the user clicks submit, how do I stop it forwarding if there are any validation errors?

The form action is:

<form name="allForm" method="post" action="/SapphireWebModule/partnersearchforprojects">

Thanks once again.

[Kor]

function validate(f){
if(validate condition is not fulfiled){
alert('something');
return false
}
}

<form onsubmit="return validate(this)">

[bldstr]

Thanks for your response; however, I don't really understand JavaScript well enough to incorporate that into my existing script. I've been trying to work this out for the past few days, reading various forms and examples but I really don't get it.

The bits I can't figure out is what the (f) and (this) should be in correspondence with my exiting script.

[bldstr]

OK, I'm desperate here

I will Paypal £5 to anyone who can take this document and have the postcode validation fully work. At the moment it detects a wrongly entered postcode but does not stop the document passing to the next page if there's an error, I'm sure it would be pretty simple for anyone here to fix.

I know it's not a lot of money but it shouldn't be a big job and I can't afford any more really.

If they could also help with date validation that would be great, just PM me...

[CrazyMerlin]

in your form tag, make sure you have: onsubmit="return testPostCode()"

where testPostCode is the name of the function that tests it, if that is all you test.

if the function returns false, the form will stop where it is and not process any more.

[bldstr]

Thank you.

However, with the following code I recieve two pop up error messages, rather than just one, if the user entres an invalid postcode:

function testPostCode () {
  var myPostCode = document.getElementById('sitePostcode').value;
  if(myPostCode == '') return true;
  else if (checkPostCode (myPostCode)) {
    document.getElementById('sitePostcode').value = checkPostCode (myPostCode)
    return true;
  }
  else {alert ("Postcode has invalid format")};
  return false;
}

[CrazyMerlin]

you are calling a function inside this one: checkPostCode (myPostCode)

make sure one isn't coming from there.

also by calling:
document.getElementById('sitePostcode').value = checkPostCode (myPostCode)
after the if statement, you are actually calling the same function twice

[bldstr]

Turns out the fault was in the onclick events in the form code, I hadn't removed the line I replaced with onsubmit="return testPostCode()"

[CrazyMerlin]

All working then?

I'll be here another 5 mins if you need anything else.

[bldstr]

I've PMed you