wffweb/src/main/java/com/webfirmframework/wffweb/server/page/BrowserPage.java
public final boolean contains(final AbstractHtml tag)
            throws NullValueException, NotRenderedException {

        if (tag == null) {
            throw new NullValueException(
                    "tag object in browserPage.contains(AbstractHtml tag) method cannot be null");
        }

        if (tagByWffId == null) {
            throw new NotRenderedException(
                    "Could not check its existance. Make sure that you have called browserPage#toHtmlString method atleast once in the life time.");
        }

        final DataWffId dataWffId = tag.getDataWffId();
        if (dataWffId == null) {
            return false;
        }
        return tag.equals(tagByWffId.get(dataWffId.getValue()));
    }
public final boolean contains(final AbstractHtml tag)
            throws NullValueException, NotRenderedException {

        if (tag == null) {
            throw new NullValueException(
                    "tag object in browserPage.contains(AbstractHtml tag) method cannot be null");
        }

        if (tagByWffId == null) {
            throw new NotRenderedException(
                    "Could not check its existance. Make sure that you have called browserPage#toHtmlString method atleast once in the life time.");
        }

        final DataWffId dataWffId = tag.getDataWffId();
        if (dataWffId == null) {
            return false;
        }
        return tag.equals(tagByWffId.get(dataWffId.getValue()));
    }
To check if the given tag exists in the UI. <br>
NB:- This method is valid only if {@code browserPage#toHtmlString} or
{@code browserPage#toOutputStream} is called at least once in the life
time.

@param tag
the tag object to be checked.
@return true if the given tag contains in the BrowserPage i.e. UI. false
if the given tag was removed or was not already added in the UI.
@throws NullValueException
throws this exception if the given tag
is null.
@throws NotRenderedException
if the {@code BrowserPage} object is not
rendered. i.e. if
{@code browserPage#toHtmlString} or
{@code browserPage#toOutputStream} was
NOT called at least once in the life
time.
@since 2.1.7
@author WFF