"HTML5 and CSS3 basic course" study Notes--supplement

<span id="Label3"></p><p><p>In HTML5, spaces and slashes at the end of an empty element are optional, but in XHTML there must be slashes, so it's best to write the slash every Time.</p></p><p><p>Disabled and required can have attribute values, or they can not have property values</p></p><p><p>1) attribute value: disabled= "disabled" required= "required"</p></p><p><p>2) no attribute value: disabled, required, But the review element is: disabled= "" required= ""</p></p><p><p>File name:</p></p><p><p>1) file names are all lowercase so that visitors are easily accessible</p></p><p><p>2) file name separated use-, do not use _, because _ Search engine optimization of the degree of support is inferior-</p></p><p><p>3) the names of the folders all use lowercase</p></p><p><p>Advantages of using semantics</p></p><p><p>1) improved accessibility and interoperability</p></p><p><p>2) Improve search engine optimization effect</p></p><p><p>3) easier to maintain and add styles</p></p><p><p>4) less code, faster loading</p></p><p><p>Disable Chrome Cache</p></p><p><p>Developer tools à right lower corner gear icon Àsettingsàgeneralàdisable Cache</p></p><p><p>After that, if you do not close the developer tool, the cache will be Disabled.</p></p><p><p>Title</p></p><p><p>The core content is placed in the first 60 characters (including spaces)</p></p><p><p>Role increases accessibility</p></p><p><p>1) Page-level Header role= "banner"</p></p><p><p>2) nav role= "navigation"</p></p><p><p>3) Main role= "main"</p></p><p><p>4) aside role= "complementary"</p></p><p><p>5) footer role= "contentinfo" at the page level</p></p><p><p>HTML5 new Element (partial)</p></p><p><p>1) <time> can add attribute datatime= "" is for machine preparation</p></p><p><p>Can be used to display the date, time, and time period we want</p></p><p><p>2) meter represents the value of the fraction and the measurement within the known range</p></p><p><p>IE9 is not supported, it will display the text content</p></p><p><p>The low, high, and optimum properties are used to set the three range</p></p><p><p>There are also min, max, default 0/1.0.</p></p><p><p>3) Progress</p></p><p><p>Support for value, max, form (if The progress bar is not nested within the form element, and it is linked, you can add the Form's properties to set its value to the ID of the Form)</p></p><p><p>js, you can directly set its value, myprogress.value=45;</p></p><p><p>Svg</p></p><p><p>IE8 is not supported, but similar effects can be achieved using JavaScript such as the SVG web</p></p><p><p>Png</p></p><p><p>Supports Index-color transparency, and also supports alpha transparency (PNG-8, PNG-32).</p></p><p><p>Creating anchors and connecting anchors</p></p><p><p><H2 id= "myTitle" >