чё там вычислять, POST делается на эту же страницу
F12 > network > Preserve log
__EVENTTARGET:
__EVENTARGUMENT:
__LASTFOCUS:
__VIEWSTATE: ........
__VIEWSTATEGENERATOR: 0470EB9F
__EVENTVALIDATION: ..........
ctl00%24ContentPlaceHolder1%24OEMSearch: uuuuuuuuuuuuu
ctl00%24ContentPlaceHolder1%24OEMSearchbtn: Search
ctl00%24ContentPlaceHolder1%24OEMDistinct:
(() => {
const body = new FormData(document.forms.form1)
body.set('ctl00$ContentPlaceHolder1$OEMSearch', 'te')
fetch('./CrossReference.aspx', {
method: 'POST',
body,
}).then(r => r.text()).then(console.log)
})()