Question

http://www.position-absolute.com/articles/jquery-form-validator-because-form-validation-is-a-mess/ Iam using this form plugin.where we can call Separate function inorder to do validation

    <input type="text" id  ="empno " class="validate['required',FuncCall[empnos]]">

“Funccall[empnos]” which is File Jquery-validation-en.js will call separate JS function called empvalidate()

"empnos" : {
        "nname":"empvalidate()",
        "alertText":"* This EMP NO  is not there "      
},  
function empvalidate(){
                var empno = $("#empno").val();
                if(empno!=''){
                    $.ajaxSetup ({cache: false});
                    $.getJSON("emp.php",{'param1' : $("#param1").val(),'empno' :$("#empno").val()},
                        function (data){
                              if(data['status']==="true"){
                              exists="true";
                             }else{
                             exists="false";
                             }
                    });
                }
                return exists;
    }

From The above function iam not able to return true or false as it has anoymous function.
How can i return true when the status is true and vice versa.It is always returning me false

Answer 1

Ajax method getJSON performs asynchronously, so your method returns ‘exists’ before it requested the server for a return value.
So you need to make your ajax request as async = false, like this:

UPD: Okay, see the full version of your function:

function empvalidate() {
  var exists = false;             // default return value is false
  var empno = $("#empno").val();
  if (empno != '') {
    $.ajax({
      url: "emp.php",
      async: false,
      dataType: "json",
      data: {'param1': $("#param1").val(), 'empno': $("#empno").val()},
      success: function (data) {
        exists = data.status;     // set status of existence to outer variable
      }
    });
  }
  return exists;                  // return actual value
}

Take care, I did not test the code above, so you need to understand the reason of each line of the code.