checking user input

[LanceT]

I want to check to see if there's only letters and numbers in a field, how would I go about doing this?

[corbin]

preg_match("([a-zA-Z0-9]", $variabletocheck)

 

Look up regular expressions.

 

Also, is_numeric could be used if you were making sure a field was just numeric.

[mmarif4u]

 if ( !preg_match('/^[a-zA-Z\" "]*$/', $name) )
       {
        error('The Name that you have given is not valid.\\n'.
                'Please try again.');
          }

 

if (preg_match('#^[0-9]{3}-[0-9]{7}$#', $hp))
        {}else{
        error('The Handphone Number that you have given is not Valid.\\n'.
                  'Please try again.');
           }

[LanceT]

also what if I wanted to check underscores (_) and dashes (-) ?

[trq]

As has been said. Look up regular expressions.