Problem when requesting a form using prototype on internet explorer 8

I'm trying to make a request using prototype 1.6.1 on ie 8, the following code works on Firefox:

var myForm = document.forms[0];
myForm.request({


onSuccess: 
        funct开发者_开发问答ion(transport) {
            var url = getPath() + nomeAcao+'?modulo='+modulo;
            window.location = url;
        }
});

When debugging, i get an error on the "myForm.request" line, it says i can't call this method on this object. Anyone knows how to fix it?

instead of

myForm.request(...);

try

Form.request(myForm, ...);