def parse(self, response):

    form_node = response.xpath("//form[@method='post']")[0]
    post_url = form_node.xpath("./@action").extract_first()

    form_data = {}

    for input in form_node.xpath(".//input"):
        name = input.xpath("./@name").extract_first()
        value_attr = input.xpath("./@value")

        if name == "ctl00$cntPortal$txtCompRegNum":
            form_data[name] = "1000"
        elif name == "ctl00$cntPortal$radSearchType":
            form_data[name] = "radStartsWith"
        elif value_attr:
            value = value_attr.extract_first()
            form_data[name] = ""


    yield scrapy.FormRequest(response.url, formdata=form_data, callback=self.parse_result)


def parse_result(self, response):
print(response.xpath("//table[contains(@id,'ctl00_cntPortal_grdSearchResults')]"))