in Visualforce page Alert button in Salesforce

Alert button in Visualforce page 

Sample Code:

Visualforce page:

<apex:page controller="SampleController">
    <script>
        function callSave(){
            var r = confirm("Are you sure want to save?");
            if(r == true) {                
                callSav();
            }
        }
    </script>
    <apex:form >
        <apex:actionFunction name="callSav" action="{!sav}"/>
        <apex:pageBlock >
            <apex:pageBlockSection >
                <apex:inputField value="{!member.Name}"/>
                <apex:inputField value="{!member.E_Mail_Id__c}"/>
                <apex:inputField value="{!member.State__c}"/>
                <apex:inputField value="{!member.City__c}"/>
                <apex:inputField value="{!member.Age__c}"/>
            </apex:pageBlockSection>
            <apex:pageBlockButtons >
                <apex:commandButton value="Save" onclick="callSave();"/>
            </apex:pageBlockButtons>
        </apex:pageBlock>
    </apex:form>
</apex:page>

Apex controller:

public class SampleController {

    public Member__c member {get;set;}

    

    public SampleController() {

        member = new Member__c();

    }

    

    public void sav(){

        insert member;

        member = new Member__c();

    }

}

Output: