Javascript Issue for check boxes in gv

See more:

Javascript

Hi,
Recently i have created a functionality where checking the master check box in grid view all the check boxes get checked which is working fine. However there is a problem that on the selected rows of check boxes in grid view i have different cells whose data i wanna access on a click of button.
For that I am making use of loops but i am not able to do so as every time i reach the loop it takes me to the javascript which I am using for check box functionality.
Can anyone please point out my mistake ???

function HeaderClick(CheckBox)
{
   //Get target base & child control.
   var TargetBaseControl = 
       document.getElementById('<%= this.gvAllClients.ClientID %>');
   var TargetChildControl = "chkEmail_Single";

   //Get all the control of the type INPUT in the base control.
   var Inputs = TargetBaseControl.getElementsByTagName("input");

   //Checked/Unchecked all the checkBoxes in side the GridView.
   for(var n = 0; n < Inputs.length; ++n)
      if(Inputs[n].type == 'checkbox' && 
                Inputs[n].id.indexOf(TargetChildControl,0) >= 0)
         Inputs[n].checked = CheckBox.checked;

   //Reset Counter
   Counter = CheckBox.checked ? TotalChkBx : 0;
}

and this is my coding for the loop:

protected void btnEmail_Click(object sender, EventArgs e)
   {

       for (int ict = 0; ict < gvAllClients.Rows.Count; ict++)
       {
           CheckBox check = ((CheckBox)(gvAllClients.Rows[ict].FindControl("chkEmail_Single")));
           if (check.Checked = true)
           {
               string strDatatype = gvAllClients.Rows[ict].Cells[5].Text.ToString();
           }
       }
       }