title: PHP regex - valid float number
body: <p>I want user only input 0-9 and only once "."</p>
  
  <pre><code> patt = /[^0-9(.{1})]/
  
   1.2222 -&gt; true
   1.2.2  -&gt; false (only once '.')
  </code></pre>
  
  <p>help me , thank !</p>