How to Refresh PHP Captcha Image on Form using jQuery

How to Refresh PHP Captcha Image on Form using jQuery

Hi, can you please let me know how I can refresh an image captcha generated by PHP?
what i have is an PHP file "captcha.php" which crerats the image on the form and I
I also have following form
  2. <html>
  3. <head>
  4. <title>Test Form</title>
  5. </head>
  6. <body>
  7. <form action="validate.php" method="post">
  8. Enter Image Text
  9. <input name="captcha" type="text">
  10. <img src="captcha.php" /><br>
  11. <button type="button" id="refresher">Refresh Captcha!</button>
  12. <input name="submit" type="submit" value="Submit">
  13. </form>
  14. </body>
  15. </html>
Thanks for your time and comments