如何运行带UAC提示的HTA对话框并获取返回值，实现按钮提权

• 目标：点击HTA中的「Add Time」按钮时弹出UAC提示，验证管理员权限
• 现状：尝试多种方法均失败，要么报错，要么无法触发UAC提权流程
• 疑问：能否让HTA的部分功能以管理员权限运行，而非整个程序全程提权

以下是编写的HTA代码：

<!DOCTYPE html>
<html>
<title >Time remaining</title>
<head>

<meta charset="UTF-8" http-equiv="X-UA-Compatible" content="IE=9">
<hta:application
  applicationname="Time remaining" 
  id=oHTA
  maximizebutton=no
  windowstate="normal"
  scroll=no
  SysMenu=no
>
<script language="VBScript">
    Const DefaultWait = 30 'minutes
    Const LogoffCmd = "Shutdown.exe /l /f"
    Const RestartCmd = "Shutdown.exe -r -f"
    Const ShutdownCmd = "shutdown.exe /s /t"
    Const Logoff = True
    Const Unattended = True
    Const TestMode = False
    Const HKCU = &H80000001
    Set oWSH = CreateObject("Wscript.Shell")
    Set oFSO = CreateObject("Scripting.FileSystemObject")
    Set oReg = GetObject("winmgmts:\.\root\default:StdRegProv")
    Dim TimeLeftInSeconds,WaitTimer,Wait,PrevWait
    MyPath  = Mid(document.URL,8)
    MyName = oFSO.GetFileName(MyPath)
    MyFolder = oFSO.GetParentFolderName(MyPath)
    oWSH.CurrentDirectory = MyFolder
    document.Title = MyName
    Scale = GetScale()
    w = 300 * Scale: h = 250 * Scale
    Window.ResizeTo w, h
    Window.MoveTo (screen.availWidth - w)/2, (screen.availHeight - h)/2
    
    Sub RunAsAdmin
        If InStr(LCase(oHTA.commandLine), " /elevated") = 0 Then
            createobject("Shell.Application").ShellExecute "mshta.exe", oHTA.commandLine & " /elevated", "", "runas", 4
            self.close
        End If
    End Sub
    
    Sub window_onLoad
      ShutdownOption(0).style.zoom = Scale
      ShutdownOption(1).style.zoom = Scale
      ShutdownOption(2).style.zoom = Scale
      Wait = DefaultWait
      WaitBox.Value = Wait
      TimeLeftInSeconds = Wait * 60
      WaitBox.select
      If Unattended Then
        UpdateCountdown
        WaitTimer = Window.SetInterval("UpdateCountdown()", 1000)
      End If
      ShutdownOption(0).checked = True
      If Restart Then ShutdownOption(1).checked = True
      If Shutdown Then ShutdownOption(2).checked = True
    End Sub
    Sub document_onKeyDown
      If window.event.keyCode=13 Then RestartCountdown
    End Sub
    Sub ReSelectInput
      WaitBox.select
    End Sub
    Sub UpdateCountdown
      Hours = CInt(TimeLeftInSeconds \ 3600)
      Minutes = CInt((TimeLeftInSeconds Mod 3600) \ 60)
      Seconds = TimeLeftInSeconds Mod 60
      CountDown.innerHTML = Hours & ":" & Right("0" & Minutes,2) & ":" & Right("0" & Seconds,2)
      If TimeLeftInSeconds<=0 Then
        Cmd = LogoffCmd
        If ShutdownOption(1).checked Then Cmd = RestartCmd
        If ShutdownOption(2).checked Then Cmd = ShutdownCmd
        If TestMode Then
          MsgBox Cmd
        Else
          oWSH.Run Cmd,1,False
        End If
        self.Close
        Exit Sub
      End If
      TimeLeftInSeconds = TimeLeftInSeconds - 1
    End Sub
    Sub RestartCountdown
      If WaitTimer="" Then WaitTimer = Window.SetInterval("UpdateCountdown()", 1000)
      WaitBox.select
      If Not IsNumeric(Replace(WaitBox.Value,":",".")) Then
        WaitBox.Value = PrevWait
        WaitBox.select
        Exit Sub
      End If
      PrevWait = WaitBox.Value
      Wait = WaitBox.Value
      If InStr(Wait,":")>0 Then
        aWait = Split(Wait,":")
        Wait = aWait(0)*60 + aWait(1)
      End If
      TimeLeftInSeconds = Wait * 60
      UpdateCountdown
    End Sub
    
    Function GetScale()
      GetScale = 1.0
      Value = oWSH.RegRead("HKCU\Control Panel\Desktop\WindowMetrics\AppliedDPI")
      If Value > 96 Then
        'Custom scaling is set
        GetScale = Value/96
      Else
        'See if standard scaling is set
        Key = "Control Panel\Desktop\PerMonitorSettings"
        Result = oReg.EnumKey(HKCU, Key, ArrKeys)
        If Result=0 Then
          'Assume first monitor in list is the one we want
          For Each SubKey In ArrKeys
            Exit For
          Next
          Value = oWSH.RegRead("HKCU\" & Key & "\" & SubKey & "\DPIValue")
          If Value>0 Then GetScale = 1 + (Value * 0.25)
        End If
      End If
    End Function
    

</script>
<style>
  .body {background-color:Lavender; font-family:Segoe UI; font-size:11pt, justify-content: center;}
  h1 {color:red; text-align: center;}
  .button {width:6em}
  .radio {vertical-align:bottom}
  /* The Modal (background) */
.modal {
  display: none; /* Hidden by default */
  position: fixed; /* Stay in place */
  z-index: 1; /* Sit on top */
  padding-top: 0px; /* Location of the box */
  left: 0;
  top: 0;
  width: 90%; /* Full width */
  height: 60%; /* Full height */
  overflow: auto; /* Enable scroll if needed */
  background-color: rgb(0,0,0); /* Fallback color */
  background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}

/* Modal Content */
.modal-content {
  background-color: #fefefe;
  margin: auto;
  padding: 20px;
  border: 1px solid #888;
  width: 80%;
  text-align: center;
}

/* The Close Button */
.close {
  color: #aaaaaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
}

.close:hover,
.close:focus {
  color: #000;
  text-decoration: none;
  cursor: pointer;
}

</style>
</head>
<body>
 <div class="timer"> <h1 id=CountDown>&nbsp </h1></div>

<button id="myBtn" value="Add Time" onClick=RunAsAdmin()> Add Time</button>

<div id="myModal" class="modal">
     

  <div class="modal-content">
    <span class="close">&times;</span>
 Enter minutes to be added<br><br>
  
  <input type=text size=8 id=WaitBox>
  <input type=button class=button id=OKButton value="OK" onClick=RestartCountdown()><br><br>
  <input type=radio class=radio name=ShutdownOption onClick=ReSelectInput()>Logoff&nbsp
  <input type=radio class=radio name=ShutdownOption onClick=ReSelectInput()>Restart&nbsp
  <br><input type=radio class=radio name=ShutdownOption onClick=ReSelectInput()>Shutdown
  </div>
</div>
  
 <script>

    var modal = document.getElementById("myModal");

    var btn = document.getElementById("myBtn");

    var span = document.getElementsByClassName("close")[0];

    btn.onclick = function() {
      modal.style.display = "block";
    }

    span.onclick = function() {
      modal.style.display = "none";
    }

    window.onclick = function(event) {
      if (event.target == modal) {
        modal.style.display = "none";
      }
    }
    
</script>
</body>
</html>

内容的提问来源于stack exchange，提问作者Steve