wffweb/src/main/java/com/webfirmframework/wffweb/tag/repository/TagRepository.java
public boolean exists(final AbstractHtml tag)
            throws NullValueException, InvalidTagException {
        if (tag == null) {
            throw new NullValueException("tag cannot be null");
        }
        if (NoTag.class.isAssignableFrom(tag.getClass())) {
            throw new InvalidTagException(
                    "classes like NoTag.class cannot be used to find tags as it's not a logical tag in behaviour.");
        }
        return browserPage.contains(tag);
    }
public boolean exists(final AbstractHtml tag)
            throws NullValueException, InvalidTagException {
        if (tag == null) {
            throw new NullValueException("tag cannot be null");
        }
        if (NoTag.class.isAssignableFrom(tag.getClass())) {
            throw new InvalidTagException(
                    "classes like NoTag.class cannot be used to find tags as it's not a logical tag in behaviour.");
        }
        return browserPage.contains(tag);
    }
Checks the existence of a tag instance.

@param tag
@return true if the given tag instance exists anywhere in the browser
page.
@throws NullValueException
if the tag is null
@throws InvalidTagException
if the given tag is {@code NoTag}.
@since 2.1.8
@author WFF