Ajax Validatior
In this Article I'll Show you How to call a RequiredFieldValidator With the aid of AJAX.
Step1:- In this case,there are three controls in .aspx page
1.TextBox(txtfname)
2.Label (lblmsg) :-To show the Error Message.
3.and a Button(btnshow)
<asp:TextBox ID="txtfname" runat="server"></asp:TextBox>
<asp:Label ID="lblmsg" runat="server" Text="Please Enter your First Name" Style="color: #ff0000; display:none;"></asp:Label>
<input id="btnshow" type="button" onclick="ShowValdidator()" value="Enter" />
Note:- Here We set the style of Label(lblmsg) :- display:none :-means the label is not display.
Here We call the function ShowValdidator() on the onclick event of btnshow,by this we check the TextBox value and call the Label(error meassage)
Step2: Call Function (ShowValdidator()):
In the <head> part write the folowing code:-
<script language="JavaScript" type="text/javascript" >
var xmlHttp
var arr;
function ShowValdidator()
{
xmlHttp=GetXmlHttpObject()
var url="Default.aspx"
url=url+"?fname="+document.getElementById('txtfname').value
xmlHttp.onreadystatechange=stateChanged
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
return false;
}
function stateChanged()
{
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
{
var str;
str = xmlHttp.responseText;
if(str=="")
{
document.getElementById("lblmsg").style.display='';
}
else
{
document.getElementById("lblmsg").style.display='none';
}
}
}
function GetXmlHttpObject()
{
var objXMLHttp=null
if (window.XMLHttpRequest)
{
objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
return objXMLHttp
}
</script>
Step 3:- In behind code (C#) :-
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
if (Request.QueryString["fname"] != null)
{
string fname = Request.QueryString["fname"];
Response.Clear();
string str = fname.ToString();
Response.Write(str);
Response.End();
}
}
}
