I am new to Javascript. So I had a doubt for the following function, how to display the error message next to text box? right now it is showing a alert message, but I need to change the alert message and need to display it next to textbox?

function AllowLock(){

    if (!locker.lock.value.match(/[a-zA-Z]$/) && locker.lock.value !=) {

        locker.lock.value=;

        alert(Please Enter only valid lock);

    }

    if(locker.lock.value.length > 5)

        alert(max length exceeded);

    } 

}