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Struts and Javascript

Posted on 2003-11-26
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Last Modified: 2010-04-01
Hi experts,

Is there a way for struts to first call a javascript function (to check some value) and if it returns a certain value, continue on with the action, or if returns another value, simply display a javascript alert window and not enter the action anymore?

I have a form and a submit button (an image button), but I wanted to try and perform a validation check first using javascript and inform the user using an alert window if the value = false. If value = true, continue with the action.

Thanks!
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Question by:rusco
  • 3
7 Comments
 
LVL 35

Accepted Solution

by:
TimYates earned 25 total points
ID: 9830246
Struts is a server-side technology, and javascript is a client side technology, so there is no way for the two to communicate directly...

You can do things like "check a form is correctly filled in" using javascript

http://javascript.about.com/library/scripts/blformvalidate.htm

But you cannot pass action variables to the javascript and back again without multiple reloads and posts of the page

Tim
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LVL 2

Expert Comment

by:DidierD
ID: 9831053
You can always call some javascript functions before you submit.

  For example:

  <script>
    function myFunction(){
     //do your validation here
     if (yourValidationFunction()){
       document.yourForm.action="nextpage.do";
       document.submit();
     } else{
       alert("wrong input");
     }
    }
  </script>

 
  <input type="button" onClick="myfunction()">

 

But there is a Struts Validator for this. I used it a while ago and it works perfectly.

There are already some basic validators available. The mask can be very usefull. But you can also add your own (Javascript) to the validator-rules.xml.

For more information about this see http://jakarta.apache.org/struts/userGuide/dev_validator.html. On the bottom of this page you can see a ref to http://www.manning-source.com/books/husted/husted_ch12.pdf. Look for client side validation.

Greetz,
Didier
0
 
LVL 2

Expert Comment

by:DidierD
ID: 9831074
Should be

document.yourForm.submit();
0
 

Author Comment

by:rusco
ID: 9834590
Hi Didier!

I tried out what you said but I run into some problems with javascript. It seems that when my code goes to my javascript, it only reads the first line of code:

ex:

my function {
    alert("Hello");
    alert("Test");
}

what will be returned to me is just the alert "Hello", the next alert will not be shown anymore. Below is my actual jsp code to do this (I forgot that I will be opening a new popup for this one):

 <html:image src="/ADM/images/edit_button.gif" border="0" onclick="return false"/>

<script language="javascript"><!--begin
   
    function getConfigItemKey()
    {  

        var count = parent.configItemsListForm.counter.value;
        var newWindow;
        alert(count);

        if (count.value == 1) {
            if (newWindow) {
                newWindow.close();
                newWindow = null;
            }
           
            var test = 1;
            window.open('/ADM/SetupEditConfigItem.do?
                                    configItemKey=test','confirm','width=400,height=150');
           
        }
       
        if (count.value == 0) {
            alert("Please select a config item to edit/view");
        }
       
        if (count.value > 1) {
            alert("Please select only one config item to edit/view");
        }
    }

\\ end-->
</script>

Thanks!
0
 
LVL 2

Assisted Solution

by:DidierD
DidierD earned 25 total points
ID: 9835483
your function is wrong.

It should be something like

<script language="javascript">
function myfunction(){
  alert("Hello");
  alert("Test");
}
</script>

<html:image src="/ADM/images/edit_button.gif" border="0" onclick="myfunction()"/>


Look at my first example again. The yourValidate function returns true or false. If it returns true you do the submit or open the window by calling getConfigItemKey().

I think you want to do something like this.

<script>

   function yourValidationFunction(){
     // do your validation and return true or false
      return true;
   }

    function myFunction(){
     if (yourValidationFunction()){
        getConfigItemKey()
     } else{
       alert("wrong input");
     }
    }
  </script>

<html:image src="/ADM/images/edit_button.gif" border="0" onclick="myFunction()"/>

Hmmm Maybe i start to understand your problem. Do you mean that the html:image is doing the onclick and the submit (form action). You don't want the form action to happen.

if you use a normal HTML img the form action will not be submitted.
<img src="/ADM/images/edit_button.gif" onclick="myfunction()"> then in the javascript function you can do the submit. Like the example in my previous comment.

Greetz,
Didier
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