HTML5 provides the function of receiving and sending information between web documents. Using this function, as long as the instance of the window object where the web page is located is obtained, not only web web pages of the same origin (domain + port number) can communicate with each other, but even cross-domain communication can be achieved.
Browser support: IE8+, firefox4+, chrome8+ opera10+
1. First of all, if you want to receive messages from other windows, you must monitor the message event of the window object, as follows:
window.addEventListener ("message", function(){},false);
2. Secondly, you need to use the postMessage method of the window object to send messages to other windows. The method is defined as follows:
otherWindow.postMessage(message, targetOrigin) ;
This method uses 2 parameters. The first parameter is the text of the message sent, but it can also be any javascript object. The second parameter is the url address of the object window that receives the message (for example: http:127.0.0.1 :8080/), but we can also use the wildcard "*" in the url address string to specify all domains, but we still recommend using a specific domain name, and otherWindow is the reference to the window object to be sent.
Demo:
If I bind 2 domain names under the hosts file now:
127.0.0.1 abc.example.com
127.0.0.1 longen.example.com
Now if it is in abc.example There is an abc.html page under the .com domain, and there is a def.html page under the longen.example.com domain. Now I hope that the pages under these two different domain names can communicate with each other. The abc.html code is as follows:
<form> <p> <label for="message" style="color:red;font-size:24px;">给iframe子窗口发一个信息:</label> <input type="text" name="message" value="send" id="message" /> <input type="submit" value="submit" id="submit"/> </p> </form> <h4 id="目标iframe传来的信息">目标iframe传来的信息:</h4> <p id="test">暂无信息</p> <iframe id="iframe" src="http://longen.example.com/webSocket/def.html" style="display:none"></iframe>
The JS code is as follows:
var win = document.getElementById("iframe").contentWindow; document.getElementById("submit").onclick = function(e){ e.preventDefault(); win.postMessage(document.getElementById("message").value,"http://longen.example.com"); } window.addEventListener("message",function(e){ e.preventDefault(); document.getElementById("test").innerHTML = "从" + e.origin + "那里传过来的消息:\n" + e.data; },false);
Def.html code is as follows:
HTML code:
<form> <p> <label for="message">给父窗口abc.html发个信息:</label> <input type="text" name="message" value="send" id="message" /> <input type="submit" /> </p> </form> <p id="test2">暂无信息。</p>
The JS code is as follows:
var parentwin = window.parent; window.addEventListener("message",function(e){ document.getElementById("test2").innerHTML = "从父窗口传来的域" +e.origin + ",和内容数据:" + e.data; parentwin.postMessage('HI!你给我发了"<span>'+e.data+'"</span>。',"http://abc.example.com"); },false);
When I click on the abc.html page, I can see the effect as follows, and the content is returned from def.html . As follows:
We need to know the following information:
You can receive messages by monitoring the message event of the window object.
By accessing the origin attribute of the message event, you can get the sending source of the message.
By accessing the data attribute of the message event, you can obtain the message content.
Use the postMessage method to send messages.
By accessing the source attribute of the message event, you can obtain the window object of the message sending source (to be precise, it should be the proxy object of the window).
With the above basic knowledge points, we can extend it to the problem of implementing ajax POST cross-domain.
Two: Use postMessage knowledge points to solve POST cross-domain issues in ajax.
Principle: The principle is also very simple. If the abc.html page under our domain name abc.example.com needs to send an ajax request (cross-domain, the domain name is longen.example.com), then we should cross-page documents first The form is the same as above. We can now create a page under longen.example.com, for example, called def.html. Then we still embed a hidden domain iframe src path in the abc.html page and point to the def under the longen.example.com domain. ,html page. The process is still similar to cross-document, except that now you can write an ajax request in the window.onmessage event in the def.html page, as follows:
abc.example.com The abc.html page under abc.example.com is as follows:
html code and Same as above, the following is the JS code:
var win = document.getElementById("iframe").contentWindow; document.getElementById("submit").onclick = function(e){ e.preventDefault(); win.postMessage(document.getElementById("message").value,"http://longen.example.com/"); } window.addEventListener("message",function(e){ e.preventDefault(); alert(typeof e.data) var json = JSON.parse(e.data); console.log(json); alert(json.url) },false);
def.html code is as follows:
JS code is as follows:
//获取跨域数据 window.onmessage = function(e){ $.ajax({ url: 'http://longen.example.com/webSocket/test.php', type:'POST', dataType:'text', //data: {msg:e.data}, success: function(res) { var parentwin = window.parent; parentwin.postMessage(res,"http://abc.example.com");//跨域发送数据 } }); };
test.php code is as follows:
<?php $data=array( url =>1, name =>'2', 'xx-xx'=>"xx" ); echo json_encode($data); ?>
The above implementation method can achieve cross-domain ajax post.

html5的div元素默认一行不可以放两个。div是一个块级元素,一个元素会独占一行,两个div默认无法在同一行显示;但可以通过给div元素添加“display:inline;”样式,将其转为行内元素,就可以实现多个div在同一行显示了。

html5中列表和表格的区别:1、表格主要是用于显示数据的,而列表主要是用于给数据进行布局;2、表格是使用table标签配合tr、td、th等标签进行定义的,列表是利用li标签配合ol、ul等标签进行定义的。

固定方法:1、使用header标签定义文档头部内容,并添加“position:fixed;top:0;”样式让其固定不动;2、使用footer标签定义尾部内容,并添加“position: fixed;bottom: 0;”样式让其固定不动。

HTML5中画布标签是“<canvas>”。canvas标签用于图形的绘制,它只是一个矩形的图形容器,绘制图形必须通过脚本(通常是JavaScript)来完成;开发者可利用多种js方法来在canvas中绘制路径、盒、圆、字符以及添加图像等。

html5中不支持的标签有:1、acronym,用于定义首字母缩写,可用abbr替代;2、basefont,可利用css样式替代;3、applet,可用object替代;4、dir,定义目录列表,可用ul替代;5、big,定义大号文本等等。

html5废弃了dir列表标签。dir标签被用来定义目录列表,一般和li标签配合使用,在dir标签对中通过li标签来设置列表项,语法“<dir><li>列表项值</li>...</dir>”。HTML5已经不支持dir,可使用ul标签取代。

html5是指超文本标记语言(HTML)的第五次重大修改,即第5代HTML。HTML5是Web中核心语言HTML的规范,用户使用任何手段进行网页浏览时看到的内容原本都是HTML格式的,在浏览器中通过一些技术处理将其转换成为了可识别的信息。HTML5由不同的技术构成,其在互联网中得到了非常广泛的应用,提供更多增强网络应用的标准机。

因为html5不基于SGML(标准通用置标语言),不需要对DTD进行引用,但是需要doctype来规范浏览器的行为,也即按照正常的方式来运行,因此html5只需要写doctype即可。“!DOCTYPE”是一种标准通用标记语言的文档类型声明,用于告诉浏览器编写页面所用的标记的版本。


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