Which tag is used in <table> to create table header cell?

<table><tr>
  <th>Title 1</th>
  <th>Title 2</th>
</tr></table>

Which CSS property sets the distance between lines?

line-height word-spacing margin

.some_class {
  line-height: 150%;
}

Which function opens a new browser window.

alert() confirm() open()

document.getElementById("id_button").onclick = function(){
  window.open("http://coursesweb.net/");
}

Indicate the PHP function that returns an array with names of the files and folders inside a directory.

mkdir() scandir() readdir()

$ar_dir = scandir("dir_name");
var_export($ar_dir);

Ex/ex/vuejs Course