Click事件先判断再触发Html的function 怎么写？

Question

html
function SendMail(contractheadid)
{
    OpenWindow("./ContractFilesUpload.aspx?ContractHeadId=" + contractheadid, 420, 130);
}Code
   protected void CheckBox1_CheckedChanged(object sender, EventArgs e)
    {
        try
        {
            CheckBox cb = sender as CheckBox;
 
            int intCountHaveNoCNSpec = new ContractData().GetCountHaveNoCNSpec(guidContractHeadID);
            if (intCountHaveNoCNSpec != 0)
            {
                Response.Redirect("../PartNo/PartNoSpecEditByContractHeadID.aspx?ContractHeadID=" + guidContractHeadID.ToString());
            }
            else
            {
              //想在这里触发SendMail，怎么写
            }
        }
        catch (Exception ex)
        {
            CustomValidator1.ErrorMessage = ex.Message;
            CustomValidator1.IsValid = false;
        }
    }

Answer 1

ASPX的CheckBox1的OnClientClick=“SendMail(contractheadid)“

Answer 2

protected void CheckBox1_CheckedChanged(object sender, EventArgs e)
    {
        try
        {
            CheckBox cb = sender as CheckBox;            int intCountHaveNoCNSpec = new ContractData().GetCountHaveNoCNSpec(guidContractHeadID);
            if (intCountHaveNoCNSpec != 0)
            {
                Response.Redirect("../PartNo/PartNoSpecEditByContractHeadID.aspx?ContractHeadID=" + guidContractHeadID.ToString());
            }
            else
            {
              Response.write("<script>SendMail(...)</script>");
            }
        }
        catch (Exception ex)
        {
            CustomValidator1.ErrorMessage = ex.Message;
            CustomValidator1.IsValid = false;
        }
    }

Answer 3

Page.RegisterStartupScript("001", "<script>SendMail(contractheadid)</script>");