JavaScript and forms

A common mitigation against automated agents or scripts using curl is to havethe page with the HTML form use JavaScript to set values of some input fields,usually one of the hidden ones. Often, there is some JavaScript code thatexecutes on page load or when the submit button is pressed which sets a magicvalue that the server then can verify before it considers the submission to bevalid.

You can usually work around that by just reading the JavaScript code andredoing that logic in your script. Using the tricks inFigure out what a browser sends to check exactly what abrowser sends is then also a good help.