Validation Rule Using Javascript in Salesforce

In Fieldax&Field Service Management have tried the below feature, SOQL query on custom javascript button in order to create a validation rule on related object. Kindly see the below Code.

{!REQUIRESCRIPT(“/soap/ajax/30.0/connection.js”)}
{!REQUIRESCRIPT(“/soap/ajax/24.0/apex.js”)}

var ReferraAccepted = sforce.connection.query(“SELECT Joining_Date__c from Postion__c where id ='{!Postion__c.Id}’ limit 1”);

records = ReferraAccepted.getArray(“records”);

var accDate = records[0].Joining_Date__c;

if(accDate==null){
alert(“Please submit the completed referral form to the Clearing House as this form cannot be submitted on it’s own.”)
}
else {
alert(“Success”)
var newRecords = [];
var c = new sforce.SObject(“Postion__c”);
c.id =”{!Postion__c.Id }”;
newRecords.push(c);
result = sforce.connection.update(newRecords);
window.location.reload();
}