How can I load html page and insert its content into div element? I don't want to use ContentPanel.setUrl (for example), because it will create IFrame Is it possible?
Simply use Gxt's HtmlContainer class and it's setUrl() method:
HtmlContainer
setUrl()
http://dev.sencha.com/deploy/gxt-2.2.1/docs/api/com/extjs/gxt/ui/client/widget/HtmlContainer.html#setUrl(java.lang.String)