title: To check if a string is alphanumeric in javascript
body: <p>I want to check if a string is STRICTLY ALPHANUMERIC in javascript.
  i have tried this:</p>
  
  <pre><code>var Exp = /^[0-9a-z]+$/;
  if(!pwd.match(Exp))
  alert("ERROR")
  </code></pre>
  
  <p>But the problem with this is it passes input sting if it contains all alphabet or all numeric, i want the function to pass if it contains both Characters and Numbers.</p>