In this article, I will give you some HTML tips that will enable your web page to have a more professional quality. You can try all the codes that I give with the tips. If this piques your interest (and I know it does), then please keep reading.
The difference between a block-level element and an inline element may not be very clear. However, the following simplified definition should keep you on the right track: a block-level element is one that has a line break before and after it. An inline element is one that does not have a line break before and after it.
X and Y Coordinates
If you design web pages by hand, from time to time you may want to know the position of a point or an element. This is the JavaScript that tells you that:
<script type="text/javascript">
function coordinates(event)
{
x=event.clientX
y=event.clientY
alert("X=" + x + ", Y=" + y)
}
</script>
<body onmousedown="coordinates(event)">
You put the JavaScript in the HEAD element of the HTML file. You add the onmousedown attribute (event) to the start tag of the BODY element as shown above. With this code in effect, if you click anywhere on the client area of the web page, an alert box will pop up to show the position of the cursor. If you want to know the position of a point on a web page, just click the point. The values are given in pixels. They are measurements from the top-left corner of the client area of your web page: going to the right gives positive X values and going down gives positive Y values (which is opposite to conventional graphs).
HTML 
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HTML5 Boilerplate Introduction
