// This is my js file function validate() {

var z = document.forms["form1"]["sponsorid"].value;
if (!z.match(/^\d+/)) {
    alert("Sponsor id should be in Numbers only")
    return false
}
var z2 = document.forms["form1"]["clientname"].value;
if (!z2.match(/^[a-zA-Z_ ]+$/)) {
    alert("Client Name should be in Alphabets only")
    return false
}
var z3 = document.forms["form1"]["additionalnumber"].value;
if (!z3.match(/^\d+/)) {
    alert("Additional Number should be in Numbers only")
    return false
}
var z4 = document.forms["form1"]["district"].value;
if (!z4.match(/^[a-zA-Z_ ]+$/)) {
    alert("District should be in Alphabets only")
    return false
}
var z5 = document.forms["form1"]["mainownerid"].value;
if (!z5.match(/^\d+/)) {
    alert("Main Owner ID should be in Numbers only")
    btnsave.Click(false)
}
var z6 = document.forms["form1"]["sponsorname"].value;
if (!z6.match(/^[a-zA-Z_ ]+$/)) {
    alert("Sponsor Name should be in Alphabets only")
    return false
}
var z7 = document.forms["form1"]["mobileno"].value;
if (!z7.match(/^\d+/)) {
    alert("Mobile Number should be in Numbers only")
    return false
}
var z8 = document.forms["form1"]["emailid"].value;
if (!z8.match(/\S+@\S+\.\S+/)) {
    alert("Enter correct Email Id")
    return false
}
var z9 = document.forms["form1"]["phoneno"].value;
if (!z9.match(/^\d+/)) {
    alert("Phone Number should be in Numbers only")
    return false
}
return true

}

//This is my vb file Protected Sub btnsave_Click(sender As Object, e As ImageClickEventArgs) Handles btnsave.Click

    Dim con As SqlConnection = New SqlConnection(constring)

....content... End Sub

//This is in my aspx file <asp:ImageButton ID="btnsave" runat="server" ImageUrl="~/images/save.gif" TabIndex="02" OnClientClick="validate()" />