How to prevent to click multi submit button?

[qingwu wang]

In my jsp page,I have two submit button,they will jump to different page,but when I first clicked one button then clicked the second button as quickly,my servlet cannt do with it,I want to forward to the page when the one's first click,ignore the second click.How can I do it?
Thanx alot.

[Srinivas Jag]

Are you using Javascript to define 'submitXXX' functions for the click of the two buttons?
If so, you can try defining a flag as a global javascript variable.
This flag would be set when you click either of the buttons the first time, and submit would take place based on the state of the flag.
Hope this helps.

[Jeroen Wenting]

An alternative would be a piece of Javascript that runs in the onclick event of the button and disables the buttons before submitting the form.
That way they cannot be clicked again.

[Andres Gonzalez]

One way to do this without using javascript:
before you reach your page with the two buttons, generate a token (it can be a random number), store it in a session, and place it as a hidden value in your form.
When the user clicks the first button, get the value from the session and compare it with the hidden value. If they're the same, it means it's the first button that it was clicked. remove the token from the session.
If the user gets to click the second button, your code will check again the hidden value against the one in the session. But, since you've removed the token from the session already, the values won't be the same. You can discard this request, since you know it was the second click and not the first.
easy
[ September 09, 2003: Message edited by: Andres Gonzalez ]

[EJ Dinglasan]

Hi!
IMHO
I think that disabling the buttons before submitting is better so that the user won't be confused if which action was really submitted.
=)

[Bear Bibeault]

Since you can never rely on client-side Javascript executing, Andres solution is actually the more robust one.
In practice, I may frequently perform client-side actions to enhance the 'user experience' -- this include form data validation -- but my server-side code never assumes that any client-side code has executed.
bear

[qingwu wang]

Thanks,It's nice of you!
Because my browser cann't support javascript so much,I will take Andres' method,How can I discard request?

[Andres Gonzalez]

Originally posted by qingwu wang:
Thanks,It's nice of you!
Because my browser cann't support javascript so much,I will take Andres' method,How can I discard request?

It depends on your requirements. It's up to you on what you're gonna do once you get the unwanted request. I implemented this technique when a user was filling out his details. In this way, my data was not saved in the database twice.
If everything went ok, I forwarded the request to a thank you page. So, if the user clicked the button twice, I immediately forwarded it to thankyou.jsp, without processing anything.
hope it helps

[qingwu wang]

QTN:
My process as following
servlet(get serveral string)->jsp(ervery string generate one submit)->servlet(according to submit attribute jump to different page)->to servral different page.then the button in the jsp can't allow to click more than one time before jumping other page.

[Andres Gonzalez]

Can't you just do something like:

<font size="2">
  // snippet from servlet
  //A. get token from session
  //B. get token from hidden form value
  if (A == B)
  {
    // remove token from session
    // jump to different page
  }
</font>

and that's it. if the second request comes in, it'll do nothing, coz A not equal to B (It doesn't go inside the if statement). You know that this request should be discarded, since you've already redirected it to your jsp.
does that make sense?
[ September 09, 2003: Message edited by: Andres Gonzalez ]

[qingwu wang]

To:Andres

//in the jsp page with two submit button
session.setAttribute("flag","on");
<input type="submit" name="submit1" value="fish">
<input type="submit" name="submit2" value="water">
//in the servlet page
HttpSession hs = req.getSession(true);
if(hs.getAttribute("flag")!=null){
hs.removeAttribute("flag");
......jump to the first page
}
if(hs.getAttribute("flag")==null){
//......back to jsp page.
}

the above snippet code,when I clicked two submit button,hs.getAttribute("flag")==null ?

[Andres Gonzalez]

disclaimer: dirty code

//in the jsp page with two submit button
Random rand = new Random();
// generates a token
String token = String.valueOf(rand.nextInt(3000000));
// starts a session and put the token in it..
HttpSession session = request.getSession(true);
session.setAttribute("token",token);
[B]<INPUT TYPE="HIDDEN" NAME="token" VALUE="<%=token %>"[/B]
<input type="submit" name="submit1" value="fish">
<input type="submit" name="submit2" value="water">

In the servlet

HttpSession session = request.getSession(true);
String requestToken = request.getParameter("token"); // token from the form
String sessionToken = (String)session.getAttribute("token"); // token from the session
// now, compare them
if (requestToken.equals(sessionToken))
{
  // first click, OK !!
  // remove the token from the session 
  session.removeAttribute("token");
  //do whateva you want
}
else
{
  //if it gets here is because it's the second button clicked. Do nothing
  // you can even ommit the else statement
}

[qingwu wang]

Thanks Andres,thanks a lot!!!
I will try it!

[qingwu wang]

hello everyone!
I found a piece of js code as following,but I click the submit button,it seems no changes.I think it should change grey.

<!-- TWO STEPS TO INSTALL DISABLE SUBMIT:
  1.  Copy the coding into the HEAD of your HTML document
  2.  Add the last code into the BODY of your HTML document  -->
<!-- STEP ONE: Paste this code into the HEAD of your HTML document  -->
<html>
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
<!-- Web Site:  <a href="http://dynamicdrive.com" target="_blank" rel="nofollow">http://dynamicdrive.com</a> -->
<!-- This script and many more are available free online at -->
<!-- The JavaScript Source!! <a href="http://javascript.internet.com" target="_blank" rel="nofollow">http://javascript.internet.com</a> -->
<!-- Begin
function disableForm(theform) {
if (document.all || document.getElementById) {
for (i = 0; i < theform.length; i++) {
var tempobj = theform.elements[i];
if (tempobj.type.toLowerCase() == "submit" || tempobj.type.toLowerCase() == "reset")
tempobj.disabled = true;
}
setTimeout('alert("Your form has been submitted.  Notice how the submit and reset buttons were disabled upon submission.")', 2000);
return true;
}
else {
alert("The form has been submitted.  But, since you're not using IE 4+ or NS 6, the submit button was not disabled on form submission.");
return false;
   }
}
//  End -->
</script>
</HEAD>
<!-- STEP TWO: Copy this code into the BODY of your HTML document  -->
<BODY>
<center>
<form onSubmit="return disableForm(this);">
Name: <input type=text name=person>
<input type=submit><input type=reset disabled>
</form>
</center>
</body>
</html>

[qingwu wang]

I want to remove the form after submit on time.How can I do it?
if I delete submit button after submit?

[Gayathri Prasad]

Hi,
I think making the visibilty of the other submit button to false after u click one button would also be a good choice...
Cheers,
Gaya3
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