Do you have a problem creating an element and setting the id to empty?

Question

I intend to create a php function that creates html elements in a more agile way, the syntax should be more or less like a sublime extension does:

create("p#paragrafo.classe1.classe2.classe3=content");
a saida devera ser: <p id="paragrafo" class="classe1 classe2 classe3">content</p>

Only if I pass like this p#.classe1=content he will create <p id="" class="classe1">content</p>. You got a problem with that id=""?

The finalized function:

function create ($str) {
    $text = substr($str, strpos($str, "=") + 1);
    $close = "";
    $str = str_replace("=$text", "", $str);
    for ($i = 0, $j = substr_count($str, ">") + 1; $i < $j; $i++) {
        # substring
        $substr = ($pos = strpos($str, ">"))?substr($str, 0, $pos):$str;
        # posicao id
        $posId = strpos($substr, "#");
        # posicao class
        $posClass = strpos($substr, ".");
        # tag
        $tag = substr($substr, 0, $posId);
        # id
        $id = substr($substr, $posId + 1, $posClass - $posId - 1);
        # class
        $class = str_replace(".", " ", substr($substr, $posClass + 1));
        # nao sei o que comentar
        $close = "/$tag$close";
        $str = str_replace("$substr>", "", $str);
        # saida
        echo "$tag class='$class' id='$id'";
        echo "<br><br>";
    }
    # saida
    echo $text;
    echo "<br><br>";
    echo $close;
}

Answer 1

In accordance with the W3 (translation of mine):

ID and NAME tokens must start with a letter([A-Za-z]) and can be followed by any number of letters, digits ([0-9]), hiphens("-"), underscores("_"), colons(":") and endpoints(".").

According to this definition empty id’s are not valid. Although nothing prevents you from using them it is not possible to guarantee how the browsers will black out.

Answer 2

No problem, in case you don’t need to reference the element ID in your project.

Regarding the reply of the friend @Genos, although he cited the source of W3, the ID and NAME not necessarily need to start with lyrics.