grafana/k6 · error

no form found for selector '%s' in response '%s'

Error message

no form found for selector '%s' in response '%s'

What it means

SubmitForm parsed the response as HTML but the configured form selector (empty string means the default selector) matched zero elements. The guard fires on form.Size() == 0 — the page simply contains no <form> matching formSelector, so there is nothing to submit.

Source

Thrown at js/modules/k6/http/response.go:175

		for _, k := range params.Keys() {
			switch k {
			case "formSelector":
				formSelector = params.Get(k).String()
			case "submitSelector":
				submitSelector = params.Get(k).String()
			case "fields":
				if rt.ExportTo(params.Get(k), &fields) != nil {
					fields = nil
				}
			case "params":
				requestParams = params.Get(k)
			}
		}
	}

	form := res.HTML(formSelector)
	if form.Size() == 0 {
		common.Throw(rt, fmt.Errorf("no form found for selector '%s' in response '%s'", formSelector, res.URL))
	}

	methodAttr := form.Attr("method")
	var requestMethod string
	if methodAttr == sobek.Undefined() {
		// Use GET by default
		requestMethod = http.MethodGet
	} else {
		requestMethod = strings.ToUpper(methodAttr.String())
	}

	responseURL, err := url.Parse(res.URL)
	if err != nil {
		common.Throw(rt, err)
	}

	actionAttr := form.Attr("action")
	var requestURL *url.URL

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Verify the response actually contains a form element; print or inspect res.html() output
2. Adjust the formSelector param to a selector that matches an existing form on the page

When it happens

Trigger: Thrown at js/modules/k6/http/response.go:175 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/b87c10f397db2468. Report an issue: GitHub.