Javascript Course

Here is a simple JavaScript function that can be used to move a html element to a random direction in page.

click on the code to select it.
//sets a random absolute position to a html element; receives the html element
function moveElmRand(elm){
 elm.style.position ='absolute';
 elm.style.top = Math.floor(Math.random()*90+5)+'%';
 elm.style.left = Math.floor(Math.random()*90+5)+'%';
}

Funny example with auto-moving a button

- In the following example the moveElmRand() function is called when the mouse is over the button. 
<h4>Example auto-moving html element</h4>
<p>Try to click on the following button.</p>

<button id='btn_test'>Catch Me</button>
<script>
//sets a random absolute position to a html element; receives the html element
function moveElmRand(elm){
 elm.style.position ='absolute';
 elm.style.top = Math.floor(Math.random()*90+5)+'%';
 elm.style.left = Math.floor(Math.random()*90+5)+'%';
}

//get the #btn_test
var btn_test = document.querySelector('#btn_test');

//register to call moveElmRand() on mouseenter event to #btn_test
btn_test.addEventListener('mouseenter', function(e){ moveElmRand(e.target);});

//register click to #btn_test
btn_test.addEventListener('click', function(e){ alert('You are Good.');});
</script>

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which tag is used in <table> to create table header cell?
<thead> <th> <td>
<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);
Moving html element to a random direction

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