Implementing a Counter
/*
Mastering JavaScript, Premium Edition
by James Jaworski
ISBN:078212819X
Publisher Sybex CopyRight 2001
*/
<HTML>
<HEAD>
<TITLE>Nagging the user to register</TITLE>
<SCRIPT LANGUAGE="JavaScript"><!--
function nameDefined(c,n) {
var s=removeBlanks(c)
var pairs=s.split(";")
for(var i=0;i<pairs.length;++i) {
var pairSplit=pairs[i].split("=")
if(pairSplit[0]==n) return true
}
return false
}
function removeBlanks(s) {
var temp=""
for(var i=0;i<s.length;++i) {
var c=s.charAt(i)
if(c!=" ") temp += c
}
return temp
}
function getCookieValue(c,n) {
var s=removeBlanks(c)
var pairs=s.split(";")
for(var i=0;i<pairs.length;++i) {
var pairSplit=pairs[i].split("=")
if(pairSplit[0]==n) return pairSplit[1]
}
return ""
}
function insertSiteCounter() {
readCookie()
displayCounter()
}
function displayCounter() {
document.write('<H3 ALIGN="CENTER">')
document.write("Welcome! You've accessed this site ")
if(counter==1) document.write("for the first time.")
else document.write(counter+" times!")
document.writeln('</H3>')
}
function readCookie() {
var cookie=document.cookie
counter=0
if(nameDefined(cookie,"siteCount"))
counter=parseInt(getCookieValue(cookie,"siteCount"))
++counter
var newCookie="siteCount="+counter
newCookie += ";
expires=Wednesday, 10-Nov-10 23:12:40 GMT"
newCookie += ";
path=/"
window.document.cookie=newCookie
}
// --></SCRIPT>
</HEAD>
<BODY BGCOLOR>
<SCRIPT LANGUAGE="JavaScript"><!--
insertSiteCounter()
if(counter>=10)
alert("Don't you think its time you registered?")
// --></SCRIPT>
<H1 ALIGN="CENTER">Nagging the user to register</H1>
</body>
</HTML>
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