Avoiding Multiple Submits

whenever we are submiting a form likewise registration page ,
after the submit the form will stored and also top url is there , when we click and enter once again then  it will automatically submit the values once again  .
 then to avoid this one write this code in liferay-portlet.xml
 below <icon> tag


<action-url-redirect>true</action-url-redirect>




                                          hope this helps you...