On webUI, it is unable to click second button after first click in VBA?

[Gabbar]

It doesn't have id element into second button elements except type, value and onclick;

Below is my webUI code

 
<input type="button" value="Download onclick="javascript:__doPostBack('GridView1','Account_number$0')">

Below is my VBA code

Dim htmlDoc As HTMLDocument 
Dim MyBrowser As InternetExplorer  
Dim MyHTML_Element As IHTMLElement  
Dim myURL As String  

On Error GoTo Err_Clear  
myURL = "url......................."  
Set MyBrowser = New InternetExplorer  
MyBrowser.Silent = True  
MyBrowser.Navigate myURL
MyBrowser.Visible = True
Do
Loop Until MyBrowser.ReadyState = READYSTATE_COMPLETE
Set htmlDoc = MyBrowser.Document

htmlDoc.all.txtAccNo.Value = "0" & "" & TextBox2.Value 
htmlDoc.all.ddlReasons.Value = "1"
htmlDoc.all.txtRequester.Value = TextBox3.Text 'Enter your password here
htmlDoc.all.txtMobNo.Value = "0" & "" & TextBox1.Value
htmlDoc.all.txtLandLine.Value = ""
htmlDoc.all.txtEmailAdd.Value = Range("E15")
htmlDoc.all.ddlRelation.Value = "3"
htmlDoc.all.button1.Click

error in blow script of second button

 
htmlDoc.getElementsByXpath("input[type=""button""]").Click

Please help me, how to automate second JS button?