function ValidEmail() {
// Checks if there is valid email address provided
// 1. Search for "@" character
// 1.1. Check the number of "@" chars (1-valid, otherwise invalid)
// 2. Analyze the left side of the "@" character
// 2.1. Lenght (> 0 - valid, 0 - invalid)
// 2.2. Invalid characters (??? to find out ???)
// 2.3. Invalid characters at the beginning of the string
// 3. Analyze the right side of the "@" character
// 3.1. Divide the string into domain names ("." char as a delimiter)
// 3.2. For each domain name
// 3.2.1. Length (> 0 - valid, 0 - invalid)
// 3.2.2. Invalid characters (???)
// 3.3. For the last domain name
// 3.3.1. Check if valid (there's a subset of valid names)
    var myForm = document.form_subscribe;

    if (myForm.input_email.value.length <= 0) {
        alert("Please provide your email address!");
        myForm.input_email.focus();
        return false;
    }
    
    // to do...
    
    return true;
}

function ShowPicture(myPicture, myWidth, myHeigth) {

    myWidth = myWidth + 20;
    myHeigth = myHeigth + 20;
    
    window.open (myPicture, "PowerKaraoke", "width="+myWidth+"px,heigth="+myHeigth+"px");
    return true;
}

/* This script and many more are available free online at
The JavaScript Source!! http://javascript.internet.com
Created by: Justin Barlow | http://www.netlobo.com */

function toggleLayer(whichLayer) {
  var elem, vis;
  if(document.getElementById) // this is the way the standards work
    elem = document.getElementById(whichLayer);
  else if(document.all) // this is the way old msie versions work
      elem = document.all[whichLayer];
  else if(document.layers) // this is the way nn4 works
    elem = document.layers[whichLayer];
  vis = elem.style;
  // if the style.display value is blank we try to figure it out here
  if(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)
    vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'block':'none';
  vis.display = (vis.display==''||vis.display=='block')?'none':'block';
}