[Javascript] Loop problem with dynamic javascript using ASP

Wed Mar 19 05:13:04 CST 2003

Thanks again David,

Well i think you guessed wrong for the onSubmit as it is present in the 
declration of my form since the beginning.
I am going to try to explain what I am trying to do more precisely and 
give you all more code snippets so that you can really understand.

First, all my pages are generated dynamically by ASP ( server side 
VBscript)  pages and what I am trying to do here is to combine javascript 
with ASP to generate javascript dynamically. I know its possible and I can 
be pigheaded when it comes to try new things for my web site. I suggest 
you visit this site http://www.15seconds.com/issue/000210.htm before you 
go furher so that i am sure that you fully understand what I am trying to 
do.

The process of my test page is as follow  :

First form generation
A user gets on page jsForm.asp.  This page appears differently wether the 
server finds out  that the visitor has submited any form yet or not. If no 
form has been submited a Form is genarated. It contains only one select 
box with numbers from 1 to 5  and a submit button. This fist form is 
submited to jsForm.asp itself and is not checked by javascript. 

Seccond form generation
Now once the first form is submited, test1.asp is going to retrieve the 
value of the select box and react differently than before by generating 
another form with a variable number of text fields. This number of text 
field is defined by the number chosen in the select box earlier so if 2 
was selected, there is going to be 2 text fields. 

Now an important part I think, is that on their generation, the text 
fields are given different names : name1 , name2 etc .... 
This client side validation script ( javascript ) is generated with this 
seccond form. 
Finaly on, on the seccond form ( the one that is checked by javascript ) 
one submit button is generated.  In the form definition there is an 
onSubmit method that sends the content of the form to the CheckForm 
function that you know. 

Javascript validation
As you already know the javascript is here to perform a final validation 
of the form before it is submitted to another asp page before database 
insertion. I am using a loop to go through all the text fields ( name1, 
name2 etc ... ) to check if they have been filled. The value of Numfrm is 
a dynamic value that corresponds to the number of textfields. My loop will 
loop ( as its name suggests) through all the texfields generated and check 
that it has been filled and I am pretty sure that the problem is here ... 
but I just cant put my hands on it. 
I think the problem comes from the part  document.form1.name[i].value. In 
fact i think that the name[i] will output something like name[1], name[2] 
etc ... and i'd need it to output name1, name2, name3  etc .... 

So finaly I will give you 2 txt documents.  One is the original asp script 
with comments and the javascript, the seccond is the output of this asp 
script into a browser ( it contains only HTML and Javascript) so that you 
can see where the problem is. 

I hope that I have made my self clear enough for you all to understand 
everything . 

Anyway thanks a lot for your precious help. 

_____________________________________
IT Projects
Alexandre Zglav 
Heritage Finance and Trust Company
12 cours des bastions 
1205 Geneva
Switzerland 
Phone :  ++ 41 22 817 31 68 
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"David T. Lovering" <dlovering at gazos.com>
Sent by: javascript-admin at LaTech.edu
18.03.2003 19:20
Please respond to javascript

        To:     javascript at LaTech.edu
        cc: 
        Subject:        Re: [Javascript] Loop problem

Ah ha!  I smell an 'onSubmit' problem:

  You need to modify your original form declaration to include an 
'onSubmit' equivalence which points
to your checking routine (which can be substantially shortened, BTW), i.e;

  <form name='myForm' action='javascript:void(null)' 
onSubmit='checkForm(document.myForm)'>

  If you combine all the helpful hints together, checkForm can be reduced 
to

  <script language='JavaScript'>
  <!--
    var form1;
    function checkForm(form1) {
      if (!form) { return false; }
      if (form == '') { return false; }                                 // 
throat-scratch protection against bogus form
      if (!document.forms[form1].elements) { return false; }// cure for 
empty form syndrome
      var Numfrm = document.forms[form1].elements.length;       // notice 
that since 'form1' is a var I don't use ""
      for (var i=0; i<Numfrm; i++) {
        if (document.forms[form1].element[i].length == 0) { return false; 
}
      }
      return true;
    }
  // -->
  </script>

  Notice how 'checkName' got squished into one line of code.  Rule of 
thumb: if you are doing something
  which takes fewer lines of code to do directly than will be required for 
a function declaration, don't use a
  function.  This keeps down the burden on the heap assignments, and 
decreases the likelihood of a heap-stack
  collision -- easily the most common cause of the "blue-screen-of-death" 
(BSOD).  Sometimes I violate this
  rule if a gazillion descending field elements are nested together in the 
variable name, but I feel guilty
  about it afterwards.

  Also, the 'action' declaration I picked can be substituted out for 
anything of your choosing -- you'll
  probably want to point it to your friendly neighborhood CGI/BIN server 
which handles your other forms 
  submissions.  However, the onSubmit kicks in BEFORE the action gets 
invoked, and if checkForm returns a
  false, the action is disabled and the form contents don't go anywhere 
(in theory).  Sometimes, a broken
  FrontPage build of the form will send it on anyway, thereby crashing the 
forms server and endearing you
  (and Microsoft) to thousands of freshly outraged customers.  [Hence the 
reason I don't use FrontPage].

  Again, I caution you -- if you have ANYTHING in your form which is an 
element, but not a vanilla text
  input, this simple script won't cut it anymore, and you'll have to put 
some more hair on its chest.

  -- Dave Lovering

Alexandre Zglav wrote:
> 
> Ok thanks a lot for the tips.
> 
> I have applied a few changes to my code accordingly to your last email 
and
> the script  doesn't jam anymore. I still have a problem thought : the
> tests seem to be completely bypassed. If i try my form and leave it 
blank,
> the form is submitted and there is no alert ....
> 
> Oh and by the way you guessed right : i am trying to test variable 
amount
> of text fields passing them into CheckName
> 
> Here is the code I am using now :
> 
> 
> 
> Probably that the return true is missplaced ( its in commentary right 
now
> as I'm not sure on where to place it )
> 
> Thanks again for your help.
> 
> 
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>                             Name: New Text Document.txt
>    New Text Document.txt    Type: Plain Text (text/plain)
>                         Encoding: base64

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