[RESOLVED] Make a form field mandatory if filled in?

[ade234uk]

I have a basic form. One of the fields telephone_number1 is not mandatory.

However If someone fills it in, I would like to make it mandatory, to ensure the field is !is_numeric

This is the part I cannot get my head around. Any ideas would be appreciated.

Using the code below, common sense tells me to first check the field for a post value. Then if there is a post value check if it is numeric. If it is numeric and filled in continue.

However of course I cannot continue, since $_POST['telephone_number1] will always be TRUE

Its early in the morning, so excuse me.

if ($POST['telephone_number1'] && (!is_numeric($POST['telephone_number1'])) { $error7a='[ Please enter valid number ]'; }

[Weedpacket]

ade234uk wrote:

However If someone fills it in, I would like to make it mandatory

That doesn't really make sense; if it's mandatory then they have to fill it in - but it's only mandatory if they do fill it in - which they don't have to do - because it's not mandatory.

However of course I cannot continue, since $_POST['telephone_number1] will always be TRUE

Why? Besides, if you want to verify that a variable exists then you should be using [man]isset[/man] or [man]empty[/man], not just trying to convert it to a boolean.

[ade234uk]

Thank you for the advice