Question

<script language="javascript" type="text/javascript">
function changeDonation(){
    return document.getElementById("quantity").value;
}
</script>

This function is associated with

 <input type="number" id="quantity" min="<?php echo $minimum_donation; ?>" 
 max="100" onchange="setDonation()">

and

  <a href="<?php echo $paypal_redirect;?>" 
  onclick="location.href=this.href+''+changeDonation();return false;"> 

I want to modify my changeDonation() so that +changeDonation() is always at least the amount of $minimum_donation. Right now, its possible for users to not change the value of “quantity” and proceed with the donation value of $0.

Here is what I tried:

<script>
if (changeDonation()<3) {
    function changeDonation(){
        return 3;
    }
}
else {
    return changeDonation()
}                     
</script>

But if I do that, changeDonation is always 3. Ideally, I want 3 to be replaced by the $minimum_variable (php variable), and have it functional. I am a complete javascript noob so please forgive me for my dumbness!

Answer 1

I believe something like this is more what you are looking for.

function changeDonation() {
    var donation = document.getElementById("quantity").value;
    return Math.max(donation, <?php echo $minimum_donation; ?>);
}

Thanks to Tom and Maël Nison for the improvements