Forms

HTML forms are plain gsx — <form>, <input>, <button>, <label> are ordinary elements. The patterns here cover one language feature that makes reusable form fields clean: forwarding undeclared attributes with { attrs... }.

A reusable form field

A Field component can wrap a <label> + <input> pair without needing to redeclare every HTML attribute the input might need. Pass { attrs... } on the inner <input> and any attribute the caller supplies that is not a named param gets forwarded there directly.

package views

component Field(label string) {
	<div class="field">
		<label>{ label }</label>
		<input class="control" { attrs... }/>
	</div>
}

component LoginForm() {
	<form method="post" action="/login">
		<Field label="Email" type="email" name="email" required/>
		<Field label="Password" type="password" name="password" required/>
		<button type="submit">Sign in</button>
	</form>
}

Renders:

<form method="post" action="/login"><div class="field"><label>Email</label><input class="control" type="email" name="email" required/></div><div class="field"><label>Password</label><input class="control" type="password" name="password" required/></div><button type="submit">Sign in</button></form>

▶ Open in Playground

Field declares only one param, label string. The <input> element carries a static class="control" and then { attrs... }, which spreads the remaining caller-supplied attributes onto it at render time. The call <Field label="Email" type="email" name="email" required/> maps label to the named param; type, name, and required are undeclared so they go into attrs and are forwarded to <input>. The rendered output shows <input class="control" name="email" required type="email"/> — both the component's own class and the caller's attributes coexist on the element.

Server-side validation is ordinary Go

gsx renders the form; reading and validating the submitted data is plain net/http. Use r.FormValue, r.ParseMultipartForm, or any form-decoding library in your handler. If validation fails, pass error state as params to a component and render the form again with inline error messages — that is standard Go, not a gsx language feature.

See the Go standard library documentation for net/http.Request for request parsing, and search for form validation libraries on pkg.go.dev.