is_float not detecting float numbers

Question

I am using is_float() to check if the number entered is float or not but it keeps throwing the echo() message when I enter 3.00. Is there any other solution to it? Or am I doing anything wrong?

Here is my code:

PHP:

if(!is_float($_POST["gpa"])){
    echo "GPA must be in #.## format.";
}

HTML:

<input type="text" name="gpa" />

Answer 1

Form inputs are always a string, so the if condition will always return the error message you specified. Make use of filter_var() instead.

if(filter_var($_POST['gpa'], FILTER_VALIDATE_FLOAT) === false) {
    echo "GPA must be in #.## format.";
}

If you want to validate the format you need to use Regular Expressions.

([0-9]{1,})\.([0-9]{2,2})

You could use RegEx alone and forget about filter_var(), since it does the same.

if(preg_match('/([0-9]{1,})\.([0-9]{2,2})/', $_POST['gpa']) == 0) {
    echo "GPA must be in #.## format.";
}