Question

I have a php form that is adding information to my sql database, i need it to only accept numbers in the text box.

This is my php form

<form id="MakeBid" action="MakeBid.php" method="POST">
    <input type="hidden" name="propertyID" value="1" />
    <div>Bid Now
        <input type="text" name="pricesoldfor" />
    </div>
    <input id="submit" input type="submit" value="Submit" />
</form>

Answer 1

Client-side for feedback without loading, you can do something like

<form [...] onsubmit="if( !this.pricesoldfor.match(/\d+/) ) { 
     alert('Please enter only numbers for the price!'); return false; 
}">

(I’ve written this example inline – as your form will probably be larger, I would advise you not to use the attribute onsubmit and instead attach a proper event handler. Have a look at preventDefault() as well as this is usually a better alternative to return false.)

What you will really need to do is validate in your PHP (server-side) that it is only numbers before you save it to the database. For example like this:

if((string)(int)$input === $input) { /*was a number*/ } else { /*was not a number*/ }

Bear in mind both of these will only allow full numbers (integers), so no “35.43” or similar. Have a look at is_numeric()