<script language="JavaScript" type="text/javascript">

// getRef makes it possible to work with page elements without 
// having to use document.getElementById(obj) over and over again.

function getRef(obj){
	return (typeof obj == "string") ?
		 document.getElementById(obj) : obj;
}

// setStyle makes it easier to change the style of an item on 
// the page using its ID 

function setStyle(obj,style,value){
	getRef(obj).style[style]= value;
}

// blinkit toggles an object between visible and hidden

function blinkit(thingtoblink)
{
if (getRef(thingtoblink).style['visibility']== 'visible')
	{setStyle(thingtoblink, 'visibility' , 'hidden');}
else
	{setStyle(thingtoblink, 'visibility' , 'visible');}
}

// bodyonload tells the page to run blinkit every 2000ms (2 sec) 
// for the object with an ID of blink1

function bodyonload(){
setInterval('blinkit(\'blink1\')', 2000); 
}

onload =  bodyonload
</script>

<span style="visibility:visible;" id="blink1">This is the text to blink.</span>