Question

Have a need to append span element to DOM.

if (check smth...) {

    a = createElement('span');
    a.id = '_span';
    b = document.getElementById('container');
    b.appendChild(a);

}

What is the best way to do in “if” to prevent duplicating same element from dom tree ? It is kinda – “open the window and don’t do it again until it were closed”

Answer 1

if ( document.getElementById( '_span' ) ) {
    // Your code where you're creating your element with id "_span"
}