Javascript Form Validation Between 2 Numbers

Question

I need a form field that if a number under 21 and over 35 is entered there is a pop up up that tells them to enter a number between 21 and 35.

Firstly I have seen this one, it doesn't solve my requirements:

Form validation with Javascript - Field value must be between 2 specific numbers

I have the following and it doesn't work, any idea why?

<!DOCTYPE html>
<html>
<head>
<script>
function validateForm() {
var x = document.forms["daysCalc"]["days"].value;
if (x>=21 && x<=35) {
    alert("Number must be between 21 and 35");
    return false;
}
}
</script>
</head>

<body>
<form name="daysCalc" action="" onsubmit="return validateForm()" method="post">
Days: <input type="text" name="days">
<input type="submit" value="Submit">
</form>
</body>

</html>

Your help would be appreciated.

Thanks in advance

Because your logic is exactly the wrong way around. You're showing the error message and return false when the number is between 21 and 35. — JJJ
– JJJ, Commented Nov 15, 2014 at 9:58
Can't believe I did that! Must be to early :| Thank you for spotting it! — andy
– andy, Commented Nov 15, 2014 at 10:11

Kristoffer Svanmark · Accepted Answer · 2014-11-15 10:06:25Z

1

You're actually sending the error message when the user is entering a number within the given range, not outside the given range.

Try this:

function validateForm() {
    var x = document.forms["daysCalc"]["days"].value;
    if (x < 21 || x > 35) {
        alert("Number must be between 21 and 35");
        return false;
    }
}

answered Nov 15, 2014 at 10:06

Kristoffer Svanmark

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Hussy Borad · Accepted Answer · 2014-11-15 11:47:01Z

0

    <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.11.1.min.js"></script>

    <!DOCTYPE html>
    <html>
    <head>
    <script>
    function validateForm() {
    var x = document.forms["daysCalc"]["days"].value;
    if (x<=20 || x>=36) {
        alert("Number must be between 21 and 35");
        return false;

}
}
</script>
</head>

<body>
<form name="daysCalc" action="" onsubmit="return validateForm()" method="post">
Days: <input type="text" name="days">
<input type="submit" value="Submit">
</form>
</body>

</html>

answered Nov 15, 2014 at 11:47

Hussy Borad

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