如果javascript尚未运行，请运行javascript [英] Getting javascript to run a process if it's not already running

问题描述

如果已经没有运行，我想让Javascript运行说cmd.exe。

I want to have Javascript run say cmd.exe if there is already not one running.

我希望有一种方法让javascript看看正在运行的进程然后如果名称在列表中不运行。但如果它没有运行过程。

I was hoping there is a way to have javascript look at running processes and then if the name is in the list dont run. but if it's not run the process.

推荐答案

Javascript不是脚本操作系统级过程控制的最佳途径。如果javascript能够直接访问您的操作系统，那么浏览互联网将是一个极大的安全风险。

Javascript is not the best route for scripting OS-level process control. If javascript were able to have such direct access to your operating system, it would be an extreme security risk to ever browse the internet.

Internet Explorer确实有一个脚本机制来自javascript的Windows，但您必须调整安全设置才能允许这种情况发生。其他浏览器甚至不提供这种可能性。

Internet Explorer does have a mechanism to script Windows from javascript, but you would have to adjust your security settings to allow this to occur. Other browsers do not even offer the possibility.

在安全警告中选择允许阻止的内容后，此代码将在Internet Explorer中执行notepad.exe：

This code will execute notepad.exe in Internet Explorer, after choosing to "Allow blocked content" from the security warning:

var shell = new ActiveXObject('WScript.Shell');
shell .Run("notepad.exe");

docs： http://msdn.microsoft.com/en-us/library/aew9yb99%28v=vs.85%29.aspx

因此，我们可以使用此方法列出活动流程和，以便在适当时启动一个：

So, we can use this method to both list active processes and to start one if it is appropriate:

function startUniqueProcess(process_name, process_path) {
    // create a shell object and exec handle
    var shell = new ActiveXObject('WScript.Shell');
    var handle = shell.Exec("tasklist.exe");

    // loop through the output of tasklist.exe
    while (!handle.StdOut.AtEndOfStream) {
        // grab a line of text
        var p = handle.StdOut.ReadLine();
        // split on space
        p = p.split(' ');
        // check for split lines longer than 2
        if (p.length < 2)
            continue;
        // match process_name to this item
        if (p[0] == process_name) {
            // clean up and return false, process already running
            shell = null;
            handle = null;
            return false;
        } // end :: if matching process name
    } // end :: while

    // clean up
    handle = null;

    // process not found, start it
    return shell.Exec(process_path);
}


// example use
var result = startUniqueProcess('notepad.exe', 'notepad.exe');
if (result === false)
    alert('did not start, already open');
else
    alert('should be open');

请记住，这是一个概念的证明 - 在实践中我不会建议你永远，永远这样做。它是特定于浏览器的，危险的，可利用的，并且通常是不好的做法。 Web语言适用于Web应用程序，尽管Microsoft可能想要告诉您，但javascript并不是一种操作系统脚本语言。 ：）

Keep in mind, this is proof of a concept - in practice I would not suggest you ever, ever, ever do this. It is browser-specific, dangerous, exploitable, and generally bad practice. Web languages are for web applications, javascript is not intended to be a OS scripting language despite what Microsoft might want to tell you. :)

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