Hi Every one,

I am new to apex.in my apllication i want check the value of the field.if the value exists i have to dispaly the alert box in VF page.if any one knows plz help me with the code.tell me the correct way to do this functionality.plz help me.

plz tell me how to write the apex class for this page.

Here my code is:

<apex:page standardController="CAF_Bank__c" extensions="cafbank"  >
    <apex:form >
        <apex:pageBlock >
                    <!-- PAGE BLOCK SECTIONS-->
            <apex:pageBlockSection columns="1" showHeader="true" title="CAF Bank Info">
          
              <apex:inputField value="{!CAF_Bank__c.Bank_Name__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Branch_Code__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Branch_Name__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Credit_Limit__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Manager_Name__c}"/>                      
              <apex:inputField value="{!CAF_Bank__c.Address_1__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Address_2__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Area__c}"/>                       
              <apex:inputField value="{!CAF_Bank__c.City__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Pin_Code__c}"/>
              <apex:inputField value="{!CAF_Bank__c.State__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Country__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Telephone_No__c}"/>                 
              <apex:inputField value="{!CAF_Bank__c.Mobile_Telephone_No__c}"/>
              <apex:inputField value="{!CAF_Bank__c.Fax__c}"/>                                   
             
           </apex:pageBlockSection>  
              
             
            <!-- PAGE BLOCK BUTTONS-->
            <apex:pageBlockButtons location="both">
           
                <apex:commandButton action="{!save}" value="Save"/>
                <apex:commandButton action="{!cancel}" value="Cancel"/>
                
            </apex:pageBlockButtons>
            <apex:pageMessages ></apex:pageMessages>
        </apex:pageBlock>
    </apex:form> 
</apex:page>

Thanks,

manu..