使用iframe中的英寸长轮询＆QUOT; withouth的产生闪烁的浏览器 [英] Using iframe for "long polling" withouth causing flashing browser
问题描述
我需要检查，如果命令被写入到一个txt文件，以更新我的网页浏览器内的三维窗口。这就是所谓的推的技术或长轮询以通知客户端。随着浏览器的必须 Internet Explorer的我有点有限。
I need to check if commands are written to a txt file in order to update a 3D window inside my web browser. This is what is known as "push" technique or long polling to notify the client. As the browser has to be Internet Explorer I am a bit limited.
我想出了使用隐藏的iframe调用重新加载每秒检查txt文件PHP脚本的解决方案。
I have come up with a solution using a hidden iframe that calls a php script that reloads every second to check the txt file.
<iframe noresize scrolling="no" frameborder="0" name="loader" src="loader.php">
在loader.php基本上做到这一点：
The loader.php basically does this:
//check txt and get commands
<body onLoad="window.setInterval('location.reload()',1000);"></body>
我看到的唯一的问题是，每一秒在网络浏览器的刷新按钮闪烁。尽管此窗口不闪烁，只是按钮，我仍然觉得有点讨厌。
The only problem I see is that every second in the web browser the reload button flashes. Although the window is not flashing, just the button, I still find it a bit annoying.
是否有此问题的一个更好的解决办法，还是与IE浏览器兼容？
Is there a better solution for this problem, still compatible with IE?
推荐答案
最后，许多尝试后，我设法使它工作，我认为最佳的标准溶液：一个长轮询Ajax解决方案。由于这给在IE7很多问题，我会贴上我的codeS下面。
Finally, after many tries I managed to make it work which I consider the optimal standard solution: a long polling ajax solution. As this gives many problems in IE7, I will paste my codes below.
首先我的PHP文件，该文件中读取一个txt和呼应的JSON的文本。
First my PHP file, which reads a txt and echoes a JSON with the text.
<?php
$commandFile = fopen("./command.txt","r");
fseek($commandFile, 0);
$command = fscanf($commandFile, "%s\n"); //reads the command
fclose($commandFile);
if($command[0] != "")
{
$commandFile = fopen("./command.txt","w"); //delete first line
fclose(commandFile);
echo json_encode($command[0]);
}
?>
现在，该HTML主页需要一种机制来调用一个函数递归的launchs这个PHP文件，并检查了答案。我的功能是这样的。
Now, the HTML main page needs a mechanism to call a function recursively that launchs this PHP file and checks the answer. My function is something like this.
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript" charset="utf-8"></script>
</head>
<body>
<script type="text/javascript">
function longPolling()
{
$.ajaxSetup({ cache: false }); //This line is THE KEY to work under Internet Explorer
$.ajax({
type: "GET",
url: "loader.php",
dataType: 'json',
async: true,
success: function(response){
if(response!=""){
sendCommand(response); //could be any other function
}
//longPolling();
setTimeout(longPolling,1000);
},
error: function(){
//longPolling();
setTimeout(longPolling,1000);
}
});
};
$(document).ready(function(){ /*waits till the whole page loads*/
longPolling(); /*start the initial request*/
});
</script>
</body>
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