Public Class Form1
    Dim WithEvents mydoc As System.Windows.Forms.HtmlDocument
    Dim mylink As System.Windows.Forms.HtmlElement
    Dim str As String

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        WebBrowser1.Navigate("www.youtube.com")
    End Sub

    Private Sub Button1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles Button1.DragDrop
        Dim wb As WebBrowser
       wb = CType(sender, WebBrowser)
        str = getContent(mydoc.Url.AbsoluteUri.ToString)
(I dont know what to write in below line)
      'Button1.Image = e.Data.GetData(DataFormats.StringFormat)
    End Sub



    Private Sub Button1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles Button1.DragEnter
        Button1.AllowDrop = True
        e.Effect = e.AllowedEffect
         End Sub

    
  
    Private Sub WebBrowser1_DocumentCompleted(ByVal sender As Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
        Try

            mydoc = WebBrowser1.Document
                      mydoc.AttachEventHandler("OnMouseDown", AddressOf mylink_MouseDown)

                           Catch ex As Exception
            MsgBox(ex.Message)
        End Try
         End Sub


    Private Sub mylink_MouseDown(ByVal sender As Object, ByVal e As EventArgs)
        Try
            Dim wb As WebBrowser
            wb = CType(sender, WebBrowser)
            wb.DoDragDrop(wb.Document, DragDropEffects.Copy)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

    End Sub
    Private Function getContent(ByVal url As String) As String

        Dim buffer As String
        Try

                      Dim req As HttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)
            req.AllowWriteStreamBuffering = True
        
                       Dim resp As HttpWebResponse = CType(req.GetResponse(), HttpWebResponse)
            Dim sr As StreamReader = New StreamReader(resp.GetResponseStream())
            buffer = sr.ReadToEnd()
            sr.Close()

        Catch exp As Exception

            buffer = "Error: " + exp.Message.ToString()
        End Try

        Return buffer
    End Function
  
End Class