Wipe, in a computing context, means  to render all data on a hard drive unreadable. The term is often used in reference to making data stored on a computer, smartphone or tablet inaccessible before disposing of the device.
A semantic HTML tag is one that defines a meaning to the enclosed content that a computer can be programmed to understand. In most cases, browsers create some visual difference to content in semantic tags, for example, content in the CODE element is usually displayed in a monospaced font. But this is not a requirement. Many people feel that semantic HTML elements are a waste of bandwidth.
Definition and Usage. The <html> tag tells the browser that this is an HTML document. The <html> tag represents the root of an HTML document. The <html> tag is the container for all other HTML elements (except for the <!DOCTYPE> tag). HTML5 has added a new attribute: manifest. The xmlns attribute is required in XHTML, but is invalid in HTML.