【IT168 技术】之前的博文中，一直有关注一些HTML 5中的值得关注但少用的API或者tips，这次继续小结一些。
1.element.classList
详细的可以参考这里
这里简单说下，它其实是一个快速对某个元素的class进行操作的新的DOM API了，比如包括了add,remove，toggle,contains的方法，比如：
1 myDiv.classList.add('myCssClass');
2 myDiv.classList.remove('myCssClass');
3 myDiv.classList.toggle('myCssClass'); //now it's added
4 myDiv.classList.toggle('myCssClass'); //now it's removed
5 myDiv.classList.contains('myCssClass'); //returns true or false
2 myDiv.classList.remove('myCssClass');
3 myDiv.classList.toggle('myCssClass'); //now it's added
4 myDiv.classList.toggle('myCssClass'); //now it's removed
5 myDiv.classList.contains('myCssClass'); //returns true or false
现在的浏览器支持情况为：
chrome 8.0+,ie 10,opera 11.5,safari 5.1
2.ContextMenu上下文菜单API
这个API是HTML 5的，用来可以生成简单的可以点击的上下文菜单，能给用户快速的选择和显示，比如:
1 <section contextmenu="mymenu">
2 <!--
3 For the purpose of cleanliness,
4 I'll put my menu inside the element that will use it
5 -->
6
7 <!-- add the menu -->
8 <menu type="context" id="mymenu">
9 <menuitem label="Refresh Post" onclick="window.location.reload();" icon="/images/refresh-icon.png"></menuitem>
10 <menu label="Share on..." icon="/images/share_icon.gif">
11 <menuitem label="Twitter" icon="/images/twitter_icon.gif" onclick="goTo('//twitter.com/intent/tweet?text=' + document.title + ': ' + window.location.href);"></menuitem>
12 <menuitem label="Facebook" icon="/images/facebook_icon16x16.gif" onclick="goTo('//facebook.com/sharer/sharer.php?u=' + window.location.href);"></menuitem>
13 </menu>
14 </menu>
15 </section>
2 <!--
3 For the purpose of cleanliness,
4 I'll put my menu inside the element that will use it
5 -->
6
7 <!-- add the menu -->
8 <menu type="context" id="mymenu">
9 <menuitem label="Refresh Post" onclick="window.location.reload();" icon="/images/refresh-icon.png"></menuitem>
10 <menu label="Share on..." icon="/images/share_icon.gif">
11 <menuitem label="Twitter" icon="/images/twitter_icon.gif" onclick="goTo('//twitter.com/intent/tweet?text=' + document.title + ': ' + window.location.href);"></menuitem>
12 <menuitem label="Facebook" icon="/images/facebook_icon16x16.gif" onclick="goTo('//facebook.com/sharer/sharer.php?u=' + window.location.href);"></menuitem>
13 </menu>
14 </menu>
15 </section>
3.element.dataset
这个API用来获得键值对的时候很有用：
比如：
1 <div id="myDiv" data-name="myDiv" data-id="myId" data-my-custom-key="This is the value"></div>
则通过下面这些可以获得键值对，这个用在jquery mobile中很实用：
1 // 获得元素
2 var element = document.getElementById("myDiv");
3
4 // 获得id
5 var id = element.dataset.id;
6
7 // 获得data-my-custom-key"
8 var customKey = element.dataset.myCustomKey;
9
10 // 设置新的值
11 element.dataset.myCustomKey = "Some other value";
2 var element = document.getElementById("myDiv");
3
4 // 获得id
5 var id = element.dataset.id;
6
7 // 获得data-my-custom-key"
8 var customKey = element.dataset.myCustomKey;
9
10 // 设置新的值
11 element.dataset.myCustomKey = "Some other value";
4.postMessage API
这个居然在IE 8后就支持了，可以支持在不同domain的iframe中传递消息。
1 // From window or frame on domain 1, send a message to the iframe which hosts another domain
2 var iframeWindow = document.getElementById("iframe").contentWindow;
3 iframeWindow.postMessage("Hello from the first window!");
4
5 // From inside the iframe on different host, receive message
6 window.addEventListener("message", function(event) {
7 if(event.origin == "http://davidwalsh.name") {
8 // Log out the message
9 console.log(event.data);
10
11 // Send a message back
12 event.source.postMessage("Hello back!");
13 }
14 ]);
2 var iframeWindow = document.getElementById("iframe").contentWindow;
3 iframeWindow.postMessage("Hello from the first window!");
4
5 // From inside the iframe on different host, receive message
6 window.addEventListener("message", function(event) {
7 if(event.origin == "http://davidwalsh.name") {
8 // Log out the message
9 console.log(event.data);
10
11 // Send a message back
12 event.source.postMessage("Hello back!");
13 }
14 ]);
5.autofocus
这个很简单了，自动focus到控件。
1 <input autofocus="autofocus" />
2 <button autofocus="autofocus">Hi!</button>
3 <textarea autofocus="autofocus"></textarea>
2 <button autofocus="autofocus">Hi!</button>
3 <textarea autofocus="autofocus"></textarea>
