To check whether a string has no whitespace, use the preg_match() in PHP.

1. Code:

<?php
   function checkStringHasNoWitespace($string){
	if ( preg_match('/\s/',$string) ){
               return "The string (".$string.") has the space";
        } else {
               return "The string (".$string.") has not the space";
        }
   }
$name="John Smith";
echo checkStringHasNoWitespace($name);
  ?>
  

2. Example:

Input:

string: "John Smith"

Output:

The string (John Smith) has the space