How to exhibit popup text message on website visits?

Show popup text message when somebody visits on your website

Just edit yellowish marked lines inwards your text as well as glue this code afterward <head> inwards your index.html webpage or on other webpage where y'all desire to present popup message.

<script>
//Alert message i time script past times Vishal Jaiswal.
//Visit http://www.vikinspire.com for this script.
//specify message to alert
var alertmessage="Welcome to website."
///No editing required beyond here/////
//Alert solely i time per browser session (0=no, 1=yes)
var once_per_session=1
function get_cookie(Name) {
var search = Name + "="
var returnvalue = "";
if (document.cookie.length > 0) {
    offset = document.cookie.indexOf(search)
    if (offset != -1) { // if cookie exists
      offset += search.length
      // ready index of showtime of value
      destination = document.cookie.indexOf(";", offset);
      // ready index of destination of cookie value
      if (end == -1)
         destination = document.cookie.length;
      returnvalue=unescape(document.cookie.substring(offset, end))
      }
   }
provide returnvalue;
}
function alertornot(){
if (get_cookie('alerted')==''){
loadalert()
document.cookie="alerted=yes"
}
}
function loadalert(){
alert(alertmessage)
}
if (once_per_session==0)
loadalert()
else
alertornot()
</script>