Why do await Task.Delay(10); stops execution in unity Web-GL?

I am using await Task.Delay(10); in unity C# for delay .After build and run in Web-GL format .The execution stops at this line that has delay .When I remove the delay it executes. This is function where delay is to be used.

  public async Task ObjSupport_PositionArrivedAsync(string Coordinate, double Value)
 {
     XAxis = GameObject.Find("X-Axis");
     ZAxis = GameObject.Find("Z-Axis");
    switch (Coordinate)
     {
         case "X-":
             {
                //code for case X-
             }
             break;
         case "X+":
             {
                    Value = Value - 100; //Total cube - x value
                     float izvalue = (float)Value;
                     izvalue = izvalue * 0.001f;
                     Debug.Log(izvalue);
                     Vector3 XAxisposition = XAxis.transform.localPosition; //get head position
                     float XAxiscurrentXpos = XAxisposition.x;
                     if (XAxiscurrentXpos <= -izvalue)
                     {
 
                         Debug.Log("XAxisSmaller");
 
 
                         while (XAxiscurrentXpos <= -izvalue)
                         {
                             await Task.Delay(1);
                             XAxiscurrentXpos += 0.001f;
                             Vector3 posx = new Vector3(XAxiscurrentXpos, XAxisposition.y, XAxisposition.z);
                         XAxis.transform.localPosition = posx;
                      
                     }
 
                     }
                     else
                     {
                         if (XAxiscurrentXpos > -izvalue)
                         {
                             Debug.Log("XAxisGreater");
                             while (XAxiscurrentXpos >= -izvalue)
                             {
 
                                 await Task.Delay(0);
                                 XAxiscurrentXpos -= 0.001f;
                                 Vector3 posX = new Vector3(XAxiscurrentXpos, XAxisposition.y, XAxisposition.z);
                              XAxis.transform.localPosition = posX;
                            
                         }
                         }
                     }
                 }
          break;
 case "Z+":
             { //code for Z+ axis }
 break;
 }
 }

And the following is code from where the above function is called.

  public async void ExecuteFile()
    {          
     string lGMCode;
     /// aList is a ArrayList object and fill in
     /// ValidateFile function.
     for (int i = 0; i < aList.Count; i++)
     {
           lGMCode = aList[i].ToString();
             if (lGMCode.StartsWith("X"))
             {
               XValue = Convert.ToDouble(lGMCode.Substring(1, lGMCode.Length - 1));
               if (XValue<0)
                     {
                       await arr.ObjSupport_PositionArrivedAsync("X-",  XValue); 
                     }
                     else
                     {
                        
                             await arr.ObjSupport_PositionArrivedAsync("X+", XValue );
                       
                     } 
           if (lGMCode.StartsWith("Z"))
             { //code for Z
       }}

Now this is all I am doing .I work fine in windows but when i build it in WEbGl format then it causes problem and stops execution on delay line. Now Kindly suggest me solution.