@Override
public void changed(ObservableValue<? extends Document> observableValue, Document oldDoc, Document newDoc)
{
    if (newDoc == null)
    {
        return;
    }
    NodeList elements = newDoc.getElementsByTagName("input");
    for (int i = 0; i < elements.getLength(); i++)
    {
        HTMLInputElementImpl element = (HTMLInputElementImpl) elements.item(i);
        String key = getInputKey(element);
        if (key == null || key.isEmpty())
        {
            continue;
        }
        setInputValue(element, character.getPreviewSheetVar(key));
        element.addEventListener("change", evt ->
        {
            HTMLInputElement input = (HTMLInputElement) evt.getCurrentTarget();
            character.addPreviewSheetVar(getInputKey(input), getInputValue(input));
        }, false);
    }
}
 

@Override
public void changed(ObservableValue<? extends Document> observableValue, Document oldDoc, Document newDoc)
{
    if (newDoc == null)
    {
        return;
    }
    NodeList elements = newDoc.getElementsByTagName("input");
    for (int i = 0; i < elements.getLength(); i++)
    {
        HTMLInputElementImpl element = (HTMLInputElementImpl) elements.item(i);
        String key = getInputKey(element);
        if (key == null || key.isEmpty())
        {
            continue;
        }
        setInputValue(element, character.getPreviewSheetVar(key));
        element.addEventListener("change", evt ->
        {
            HTMLInputElement input = (HTMLInputElement) evt.getCurrentTarget();
            character.addPreviewSheetVar(getInputKey(input), getInputValue(input));
        }, false);
    }
}
 

private String getInputValue(HTMLInputElement input)
{
    if (isCheckable(input))
    {
        return Boolean.toString(input.getChecked());
    } else
    {
        return input.getValue();
    }
}
 

private void setInputValue(HTMLInputElement input, String previewSheetVar)
{
    if (isCheckable(input))
    {
        input.setChecked(Boolean.parseBoolean(previewSheetVar));
    } else
    {
        input.setValue(previewSheetVar);
    }
}
 

private String getInputValue(HTMLInputElement input)
{
    if (isCheckable(input))
    {
        return Boolean.toString(input.getChecked());
    } else
    {
        return input.getValue();
    }
}
 

private void setInputValue(HTMLInputElement input, String previewSheetVar)
{
    if (isCheckable(input))
    {
        input.setChecked(Boolean.parseBoolean(previewSheetVar));
    } else
    {
        input.setValue(previewSheetVar);
    }
}
 

public UserCredentials(HTMLInputElement username, HTMLInputElement password){
	this.username = username;
	this.password = password;
}
 

private boolean isCheckable(HTMLInputElement input)
{
    String type = input.getAttribute("type").toLowerCase();
    return "checkbox".equals(type) || "radio".equals(type);
}
 

private String getInputKey(HTMLInputElement input)
{
    return input.getAttribute("target_var");
}
 

private boolean isCheckable(HTMLInputElement input)
{
    String type = input.getAttribute("type").toLowerCase();
    return "checkbox".equals(type) || "radio".equals(type);
}
 

private String getInputKey(HTMLInputElement input)
{
    return input.getAttribute("target_var");
}