Ajax calling situation on asynchorous call - ajax

Question

I am stuck with my specific problem.
I want to return false if the data comes using ajax.
Here is my code:
<script>
function verifydom(form)
{
var domnam = form.domname.value;
if (domnam == "")
{
alert("Please enter the Domain Name");
form.domname.focus();
return false;
}
else if(domnam.indexOf('.gov.in') <= 0){
alert("Please enter valid domain name");
form.domname.focus();
return false;
}
else{
$.ajax({
type: "get",
url: "calling.php",
data: "domnam="+domnam,
success: function(msg){
if(msg!== ""){
alert(msg);
}
}
});
return false;
}
return true;
}
</script>
<form name="frmDelegate" action="dlgdetail.php" method="POST"
onsubmit="return verifydom(document.frmDelegate);" autocomplete="off">
input type="text" name="domname" id= "domname"
onkeyup="showResult(this.value);"/> <input type="hidden"
id="chkmsg" value=""/>
<input type="submit" value="Go" name="submit" />
</form>
The ajax call under 'else condition' would return some error message, So if an error comes, I want the form not to be submitted.
Okay, the problem is 'Else will work every time whether Ajax gives a message or not.
How can I overcome this situation?

Answer 1

Rather than blank message I would prefer to return a JSON message from the calling.php file.
$arr = array( "status" => "error", "message" => "error found");
echo json_encode($arr);
By doing this you are easily allowed to check whether the error is there or not. If JSON have any message then you should check by below code.
$.ajax({
type: "get",
url: "calling.php",
data: "domnam="+domnam,
success: function(msg){
var data = jQuery.parseJSON(msg);
if(data.status == "error"){ // no need to check strictly
return false;
}
}
});