Code checks "submit" type button

[Ivan Turner]

The code "if(request.getParameter("post") != null )" and "if(request.getParameter("addBulletin") != null" is testing whether a button was clicked within jsp. How does a button become not null and with what not null value is it populated? I can't find the answer on google.

<% if(request.getParameter("post") != null ) { %>
	  <h2><%= topic %> Bulletin Board</h2>  <form action="ch8example9.jsp" method="post">
	  <textarea name="message" cols="25" rows="5"></textarea>
	  <input type="hidden" name="topic" value="<%= topic%>"><br>
	  <input type="submit" name="addBulletin" value="post bulletin">
	  </form>
<% }%>
<% if(request.getParameter("addBulletin") != null &&
      !request.getParameter("message").equals("")) {
%>

Thanks

[Ivan Turner]

A quick out.println("**"+request.getParameter("post")+"**"); indicated that the value attribute of the input tag not only shows as the button's text but it is also the value associated with getParameter. I didn't need google after all!!!

[Ashwini Kashyap]

Hi Ivan,

The approach with which you are checking the click event of the button is absolutely incorrect.
Make use of javascript or JQuery to check events like button clicked and so on.

If you choose javascript then you may make use of onclick() event of button and then invoke its function for the same.

Let me know if you have any further concerns.

Thanks and Regards,
Ashwini Kashyap