how to request a hidden field value on servlet with post method?

[moshik salem]

hi,

i am trying to get a hiddenField value on servlet but i am getting a null value, how to solve this?

my jsp code look like this:

<form action="ImageResizeServlet" method="post">
<input type="hidden" id="pageWidth" name="pWidth"></input>
</form>

and my servlet code look like this:

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
String s=request.getParameter("pWidth");
....

what to do?
thank you.

[duy nguyen H]

Guess you need to initialize value for this field. Either by default value by yourself or computed value before sending it to server for further processing.

[moshik salem]

i have already intalized the value of the hiddenField with javaScript before submitting it to the servlet, but still i am getting null value.

any other idea?

[Vt Guru]

By Just with the below code how you can submit the form
<form action="ImageResizeServlet" method="post"> <input type="hidden" id="pageWidth" name="pWidth"></input> </form>

Just add one submit button in the above form and check it

[moshik salem]

thank you, when i use the submit button it works. but i want that the form will submit himself without any user interaction.

so can someone tell me how to post a form to the servlet with no button pressing or any other event?

i tried in my javaScript to do: form.submit();

but the parameters on servlet are null when i do that.

any idea?

[duy nguyen H]

Could you post javascript snippet onto the site for reviewing? No difference between click on submit button or call form.submit() from javascript code.

[Stefan Evans]

Do you want the form submitted without any user interaction?
Or do you want an HTTP request sent without user interaction?

Submitting the form will send an HTTP request - but there are other ways to do that as well.

You could just make an ajax request to the server and pass along the parameter in the url. Might be cleaner than mucking around with the form
ie send a request to ImageResizeServlet?pWidth=[valueFromJavascript]