The mark of HTML5 can be omitted. Without affecting the layout of the page, it can save the size of the webpage. Reduce code.
Some marks can be omitted.
The starting mark of omittidum does not mean that the mark does not exist, it is implicit, but it still exists. A HTML file always has a root mark HTML, even if the string <HTML> does not appear anywhere in the page mark.
The starting mark of the HTML mark can be omitted.
The end mark of the HTML mark can omit the HTML tag immediately followed with a comment immediately.
The starting mark of the headbar can be omitted. If the mark is empty, or the mark in the head is first a mark rather than a comment.
The end label of the headbar can be omitted. If the head mark is labeled, follow the space character or comment immediately.
The start mark of a body mark can be omitted. If the mark is empty, or if the first mark on the body is a space character or comment, but if the first mark of the body internal label is a script or style labeling You cannot omit the body mark.
The end label of a body mark can be omitted.
The end label of the li mark can be omitted, if the li mark is followed by another li mark or whether there is a parent label more content.
The end of a DT mark can be omitted, if the DT mark is followed by the other DT or a DD mark.
The end of the DD mark can be omitted, if DD follows another DD mark or DT mark, or there is no more content of the parent label.
The end mark of the P tag can be omitted. , HR, Menu, NAV, OL, P, Pre, Section, Table, UL, Mark, or if there is no more parent labeling content, and the parent label is not the A mark.
The end mark of an RT mark can be omitted. If the RT tags follow the RT or RP mark, or there is no more content of the parent label.
The end label of an RP mark can be omitted. If the RP mark is followed by RT or RP, or there is no parent labeling.
The end label of an Optgroup mark can be omitted.
The end label of an Option mark can be omitted. If the Option mark follows another Option mark, or follows an Optgroup mark, or there is no parent labeling more content behind.
The starting of the colgroup tag can be omitted. If the first mark in the colgroup mark is a color mark, or if it is not followed by another color, it has been omitted by the end mark. (Colryp cannot be ignored, if the mark is empty.)
The end label of the Colryp can be omitted.
The end label of thead mark can be omitted, if thead tags follows a TBODY or TFOOT mark.
The start mark of the TBODY mark can be omitted. If the TBODY mark is first is a TR mark, if the tag is not omitted after the tag, it is omitted to the end tabody, thead, and tfoot tags. (It cannot be ignored, if the mark is empty.)
The end label of the TBODY mark can be omitted.
The end label of the TFOOT mark can be omitted.
The end of a TR mark can be omitted. If TR tags keeps with another TR mark, or if there is no parent labeling more, there will be more content.
The end of a TD mark can be omitted.
The end of a TH tag can be omitted, if TH tags with TD, TH tags, or if there is no parent labeling more content.
However, if you start any or more attributes, it cannot be omitted.