Check to see if var is String or Integer

How can I check a string to see if it consists of a string or an integer? I have tried:

if($var >=1 || $var == 0)

But even if there is not # and just a string it thinks that it is equats to 0. Sometimes the number may be 0.

Is there a function that checks this, like the JS isNaN?

I found one way to accomplish what I want:

if($var >=1 || $var == '0')

I believe you are talking about php...

For simple usage, see functions like is_string() or is_integer(). For more advanced comparisons, use regExp.