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
What attribute makes a radio button or checkbox input selected?
checked="checked" selected="selected" disabled="disabled"
<input type="checkbox" name="a_name" value="value" checked="checked" />
What CSS value scales the background image to the largest size contained within the element?
repeat-x contain linear-gradient
#id {
  background:url("path_to_image.png");
  background-size:contain;
  background-repeat:no-repeat;
}
What operator is used to determine the rest of the division of two numbers?
% * /
var rest8_7 = 8 % 7;
alert(rest8_7);
Indicate the PHP function that rounds a number up to the next highest integer.
floor() ceil() abs()
$nr = ceil(3.5);
echo $nr;        // 4
Moving html element to a random direction

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