function validar(){
	var form = $('form');
	var expEmail = /^[\w-]+(\.[\w-]+)*@(([\w-]{2,63}\.)+[A-Za-z]{2,6}|\[\d{1,3}(\.\d{1,3}){3}\])$/;
	
	if(form.nome.value == "Nome"){
		alert("Informe seu nome!");
		form.nome.value = "";
		form.nome.focus();
		return false;
	}
	
	if(form.email.value == "E-mail"){
		alert("Informe seu email!");
		form.email.value = "";
		form.email.focus();
		return false;
	}
	
	if(!expEmail.test(form.email.value)){
		alert("Digite um email valido!");
		form.email.value = "";
		form.email.focus();
		return false;
	}
	
	return true;
}

function mudaValor(campo){
	
	var form = $('form');
	
	switch(campo){
		
		case 'nome':
		
		if(form.nome.value == 'Nome'){
			form.nome.value = '';
		}else if(form.nome.value == ''){
			form.nome.value = 'Nome';
		}
		
		break;
		
		case 'email':
		
		if(form.email.value == 'E-mail'){
			form.email.value = '';
		}else if(form.email.value == ''){
			form.email.value = 'E-mail';
		}
		
		break;
		
	}
	
}