Requiring User to Enter Number Which is a Certain Interval

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October 14th, 2002, 09:25 AM

aspnewbie

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Requiring User to Enter Number Which is a Certain Interval

Hi All,

I've created a asp form which requires the user to enter a number. I'm wondering if there is a way to check to ensure that the number entered is of a certain interval (say 5s) and return an error message if it doesn't meet that criteria. I would prefer to do this with javascript to avoid a trip to the server.

As javascript isn't my strong point, any assistance would be greatly appreciated!

October 14th, 2002, 10:50 AM

rdoekes

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this function should do the trick

just change the maxNumber and minNumber to the interval you would like

Code:

function checkform(oForm)
{
var maxNumber = 5;
var minNumber = 1;

formNumber = oForm.testnumber.value;
if (isNaN(formNumber))
{
  alert("formnumber is not numeric");
  return false;
}

if ( formNumber - maxNumber > 0)
{
  alert("wrong number");
  return false;
}

if ( formNumber - minNumber < 0)	
 {
  alert("wrong number");
  return false;
}
}

Call the script by <. form action="your action page" method="post" name="theForm" onSubmit="javascript: return checkForm(this)">

__________________
- Rogier Doekes

Last edited by rdoekes : October 14th, 2002 at 10:54 AM.

October 14th, 2002, 12:09 PM

aspnewbie

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Thanks a lot for the quick and detailed response! I'm a little unclear as to whether it will actually do what I want, though.

Just to give you a little more of an explanation, I need the users to enter bids in $5 denominations (it's for a online charity auction). If someone types in $31 they should get an error, but if they type in $30, then the form should submit.

With your function, if the max number is 5, then wouldn't either 30 or 31 return false because they would be greater than zero?

Last edited by aspnewbie : October 14th, 2002 at 12:23 PM.

October 20th, 2002, 12:25 PM

rdoekes

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modulus 5

Ok, I think the trick is to use the integer division function modulus in javascript (%)

Code:

function checkform(oForm)
{
 var intervalNumber = 5;


 formNumber = oForm.testnumber.value;

 if (isNaN(formNumber))
 {
  alert("formnumber is not numeric");
  return false;
 }

 if ( formNumber % intervalNumber > 0)
 {
  alert("wrong number");
  return false;
 }

}

hope this helps

October 20th, 2002, 09:43 PM

aspnewbie

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Awesome. This looks great. It shows that I should really learn more javascript, given all its functionality!

Thanks again for your help!

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