asked on

Regular expression for negative float

Hi Guys,
Need a regular expression for floating point numbers, should allow negative numbers as well.
Regards,
Ras

NetGroove

write some examples of formats you would like to accept.
Do you need only true or false with an alert in false case?

NetGroove

Here a simple check:

<script>

function isFloat(theValue){
return (/^-?\d+(\.\d+)?$/).test(theValue+'');
}

alert(isFloat(1));
alert(isFloat(-100));
alert(isFloat(12.5));
alert(isFloat('1F'));
</script>

James Rodgers

try this to see if it fits your needs

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">

<html>
<head>
      <title>Untitled</title>

<script>
      function testFloat(){
      regEx=/^-?\d*(\.\d*)?/
            if(!regEx.test(document.testForm.myFloat.value)){
                  alert("not valid");
            }
            return false;
      }
</script>
</head>

<body>
<form name="testForm" onSubmit="return testFloat()">
<input type="text" name="myFloat" value="">

<input type="submit" name="go" value="go">

</form>

</body>
</html>

rasaraja

ASKER

Jester/NetGroove,
what is the ^ for ? What is it negating ?

rasaraja

ASKER

Oops ! Sorry ..it is for begining .. that's fine..

rasaraja

ASKER

Ooops ! Sorry ..got it ..for the begining ...

rasaraja

ASKER

Jester/NetGroove, there's a problem ... having (\.\d+)? is accepting anything after a dot !

It is taking
9.a
9.bbbbb

Anything !!

Maybe we can do something like this - /^ - \d+(\.)?(\d)+/

SOLUTION

James Rodgers

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

NetGroove

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

James Rodgers

thanks for the points

NetGroove

Regular grading is an A.
B is only in the school when you are the teacher.