# How to programatically submit a form that uses document.form

**URL:** <https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923>\
**Category:** Ruby\
**Created:** [January 9, 2006, 9:24am UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923 "2006-01-09T09:24:53Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![harry](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/f6c823/32.png) [@harry](https://www.ruby-forum.com/u/harry)\
**Post date:** [January 9, 2006, 9:24am UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923/1 "2006-01-09T09:24:53Z")

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Hi there:

have been trying to use Mechanize to submit a form and scrape the  
resulting page - but realized after looking at the form page that it  
uses Javascript to perform the form submission :-/

The page with the form is built such that

The Javascript function checkSelections in turn then calls  
document.forms[0].submit();

I understand Mechanize doesn’t include a JavaScript engine and I don’t  
want to choose a platform-specific route, i.e. control Windows IE.

Has anyone experienced similar difficulties?

Thanks, Harry.

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**Author:** ![harry](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/f6c823/32.png) [@harry](https://www.ruby-forum.com/u/harry)\
**Post date:** [January 9, 2006, 2:21pm UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923/2 "2006-01-09T14:21:02Z")

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Hello.

I’m guessing checkSelections() merely verifies that the form parameters  
are in order before calling the submit action on the form. The submit  
action merely visits somepage.asp (specified in the form action  
attribute), and posts form parameters to it.

So I think visiting “somepage.asp?param1=value1”, and perhaps tacking  
on the other paramaters from the form will work.

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<div class="post-metadata">

**Author:** ![harry](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/f6c823/32.png) [@harry](https://www.ruby-forum.com/u/harry)\
**Post date:** [January 9, 2006, 9:36pm UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923/3 "2006-01-09T21:36:17Z")

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Depending on what the JavaScript is doing, you may or may not need to  
concern yourself with it. If it simply does validation, you can ignore  
it, but just make sure your script submits valid data, since the  
server probably assumes the data is valid if there is JavaScript  
validation.

If the JavaScript does some processing and adds more information to  
the form submission, then you will need to mimic this in your  
Mechanize script.

But really, in the end, the form submission will always result in a  
POST to the server, so overall you don’t need to worry about the  
JavaScript, just what kind of data the server expects to be posted.

If worse comes to worse you can always connect a transparent proxy to  
see exactly what the web page is posting, and then mimic that. A  
transparent proxy can be built in Ruby using WEBrick in a few lines.

Ryan

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<div class="post-metadata">

**Author:** ![harry](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/f6c823/32.png) [@harry](https://www.ruby-forum.com/u/harry)\
**Post date:** [January 11, 2006, 6:53am UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923/4 "2006-01-11T06:53:40Z")

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Ryan L. wrote:

> Depending on what the JavaScript is doing, you may or may not need to  
> concern yourself with it. If it simply does validation, you can ignore  
> it, but just make sure your script submits valid data, since the  
> server probably assumes the data is valid if there is JavaScript  
> validation.

Which is so wrong on so many levels, and calls for hammering the server  
with the most invalid data you can imagine.

Another possible quick hack if the JavaScript doesn’t do any processing  
is mangling the HTML of the form and adding an to  
the text before Mechanize gets it. This might end up as less typing than  
faking the POST request if we’re at the quick’n’dirty level.

David V.  
Who should spam the list less in the wee hours

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<div class="post-metadata">

**Author:** ![harry](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/f6c823/32.png) [@harry](https://www.ruby-forum.com/u/harry)\
**Post date:** [January 12, 2006, 7:05am UTC](https://www.ruby-forum.com/t/how-to-programatically-submit-a-form-that-uses-document-form/51923/5 "2006-01-12T07:05:24Z")

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You guys were right - I went down the wrong path in analyzing what the  
problem really was. My problem turned out to be me 😉 submitting the  
form with a numeric value while it expected a string. Once that was  
taken care of a simple submit worked just fine 😉

Thanks again, Harry.