How to validate multiple email address in javascript?

function validateEmail()
{  
     var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
     str = document.getElementById("txtContactEmail").value;
      var array = str.split(';');        
     for(var i =0;i<array.length;i++)
     { 
        var email = array[i];                
         if(!email.match(emailRegEx))
         {
            alert('The email address '+ ' "' +email+ '" '+ ' is invalid');
            return false;
        }
     }
     return true           
}