types/src/main/java/com/google/common/html/types/SafeHtmlBuilder.java
public SafeHtmlBuilder setFormaction(SafeUrl value) {
    if (!FORMACTION_SAFE_URL_ELEMENT_WHITELIST.contains(elementName)) {
      throw new IllegalArgumentException(
          "Attribute \"formaction\" with a SafeUrl value can only be used "
              + "by one of the following elements: "
              + FORMACTION_SAFE_URL_ELEMENT_WHITELIST);
    }
    return setAttribute("formaction", value.getSafeUrlString());
  }
public SafeHtmlBuilder setFormaction(SafeUrl value) {
    if (!FORMACTION_SAFE_URL_ELEMENT_WHITELIST.contains(elementName)) {
      throw new IllegalArgumentException(
          "Attribute \"formaction\" with a SafeUrl value can only be used "
              + "by one of the following elements: "
              + FORMACTION_SAFE_URL_ELEMENT_WHITELIST);
    }
    return setAttribute("formaction", value.getSafeUrlString());
  }
Sets the {@code formaction} attribute for this element.

<p>The attribute {@code formaction} with a {@code SafeUrl} value is allowed on these elements:

<ul>
<li>{@code button}
<li>{@code input}
</ul>

@throws IllegalArgumentException if the {@code formaction} attribute with a {@code SafeUrl}
value is not allowed on this element