checking to see if value is a integer from a form text field

hey, I have a strange problem, when a user inputs the quantity into a text input field in a cart, I want to be able to test to see if the value is a integer if it isn't then default it to 1 if ( !is_int($Qty) ) { $Qty = 1; } Looks ok, should work in theory, but it doesn't if I use this test, the update on the database fails, take it out and it works, so if a user was to type "f" in the quantity field in the cart and hit update because the quantity field is int(2) in the database it will default to 0 which I do not want. I have also tried to set the type before the update like so: $Qty = settype($Qty, "integer"); This also will make the update fail, how would I make sure a user does not type characters in the quantity field without using javascript or ereg stuff to check the values? I just want to default the quantity to 1 if a invailid quantity is inputted. If there is no obvious soulution then I will use a piece of javascript to check the field onSubmit for illegal characters and alert the user I guess. Regards, Joseph