php – How to check variables with jQuery so they are not sent empty?

Question:

I'm learning about jQuery and I've already started making Ajax requests to register the information in mysql database. I have code that has several variables and I would like to ask how I can check at once if there are any empty variables. I was thinking about doing this with array but I don't know how to use it. These variables will be captured from the form submit. I ask for help!

    var empresa;        
    var username;       
    var ativado;            
    var tipousuario;        
    var senha;              
    var nome;               
    var cpf;                
    var cnpj;               

Answer:

Sometimes client-side and server-side validation is done. There are always several ways to do this.

To do a client-side check you will have to look for element.value , element.checked depending on the type of element, and in the case of input type="radio" have to go through them all and see if one of them is selected. It might make it a little easier to add a class to these elements, but otherwise test it like this:

var validado = true, erros = 0;
$('input, select, textarea').each(function () {
    var nomeTag = this.tagName.toLowerCase()
    if (nomeTag == 'select' || nomeTag == 'textarea') validado = !!this.value;
    else if (this.type == 'checkbox') validado = !!this.checked;
    else if (this.type == 'radio') validado = !!$('input').filter(function () {
        return this.checked
    })[0];
    else validado = !!this.value

    if (!validado) {
        this.addClass('incompleto');
        erros++;
    } else {
        this.removeClass('incompleto');
    }
});
if (erros) // validacao falhou!

If the erros not 0 after this code then there are empty fields. Added an optional part to give a class to empty elements for user visibility.

On the PHP side all fields go inside $_GET or $_POST, it depends how you are using it. Then you can do a simple check with a for cycle:

foreach ($post as $chave=>$valor) if (!$valor) die('O campo '.$chave.' está  vazio!');

There are more complex methods to check the content type. In these examples, and following what you asked, this only checks for empty fields.

Attention: this verification does nothing to make the content secure, that is, this verification must be followed by another verification that prepares the content to be inserted in the database.