Center an object - vertically and horizontally

You can easily center an object on the page - both vertically and horizontally - using the HTML code example below.  It can be any object.  And it will automatically center for any size window, even if the window is re-sized.  Simply replace the <img> tag with what ever you want to be centered.

<table border="0" height="100%" width="100%">
  <tr>
    <td>
      <table border="0" align=center valign=middle>
        <tr>
          <td>
            <img src="image.gif">
          </td>
        </tr>
      </table>
    </td>
  </tr>
</table>

If you want to use code that will pass W3C Validation (the table height and valign parameters work fine but are not W3C valid), you can use the example below, but you must adjust the margin-top and margin-left to be half of the width of the image.

<div style="position: absolute; top: 50%; left: 50%; margin-top: -5px; margin-left: -25px">
  <img src="image.gif">
</div>

A collection of great HTML "One Liners"

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You can easily create a scrollable text box with this one line <div> tag.   You can put anything inside the scrollable area.   This is a very simple one line alternative to the iframe.

<div style="padding: 20px; overflow: auto; border: solid 1px black; width: 400px; height: 300px;">
Content goes here
<div >

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Use this line to pre-load those mouseover images to avoid browser delay:

<img src="image.gif" alt="" style="display: none;">

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Get rid of the IE image toolbar with this one line in the <head> section of your html:

<meta http-equiv="imagetoolbar" content="no">

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Disable the "right click" with the oncontextmenu parameter in your body tag (this parameter is not W3C standards compliant but it works with most browsers):

<body oncontextmenu="return false">

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Disable autocomplete on any input field with the autocomplete parameter in your input tag:

<input . . . autocomplete="off">

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You can tell search robots to index your main page and go no further with this one line in the <head> section of your html:

<meta name="ROBOTS" content="INDEX,NOFOLLOW">

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You do a simple redirect to another page by putting this one line in the <head> section of your html.
The zero is how many seconds to wait before doing the redirect.

<meta http-equiv="refresh" content="0;URL=http://yourdomain.com/anypage.htm">

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You force a page refresh (to keep your content current) putting this one line in the <head> section of your html.
The 300 is how many seconds to wait before doing the refresh.

<meta http-equiv="refresh" content="300">

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If your page does not need to scroll, in certain situations IE may still show the browser gutter (placeholder for the scrollbar).
Get rid of it with this one Style Sheet line:

html {overflow:auto;}

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If you want a multi-line alert box, use JavaScript alert and use "\\n" for a line break.

alert ('This is line one\\nThis is line two');