function checar_form ()  {
	if (!document.form1.nome.value)  {
		alert('Por favor, digite o nome');
		document.form1.nome.focus();
		return false;
	}
	else if (document.form1.email.value.length < 4) {
		alert('Por favor, digite o email');
		document.form1.email.focus();
		return false;
	}
 	else if ((document.form1.email.value.indexOf("@",0))== -1 || 
  (document.form1.email.value.indexOf("@",0)) < 1 || 
  (document.form1.email.value.indexOf(".",0))== -1 ||
  (document.form1.email.value.indexOf("@",0))== document.form1.email.value.length - 1 ||
  (document.form1.email.value.indexOf(".",0))== document.form1.email.value.length - 1) {
    alert("Formato de e-mail incorreto");
	document.form1.email.focus();
    document.form1.email.select();
		return false;
  }
	else {
		return true;	
	}
}