Tell a friend script

<script type='text/javascript'>
function showField(div_name)
{
 var txt = "";
 var num = document.form1.item_count.value;
 for(i = 0; i < num; i++)
 {
   txt += "<input type='text' name='friendname_" + i + "' value='name' onfocus='this.value='''/></input><input type='text' name='friendemail_" + i + "' value='email'/><br /></input>";
 }
 document.getElementById(div_name).innerHTML = txt;
}

function showDropDown()
{
 if(document.form1.checkbox_name.checked == true)
 {
   document.getElementById('dropdown').style.display = "block";
 }
 else
 {
  document.getElementById('dropdown').style.display = "none";
  document.getElementById('email_div').innerHTML = null;
 }
}
</script>

<script language = "Javascript">

function echeck(str) {

		var at="@"
		var dot="."
		var lat=str.indexOf(at)
		var lstr=str.length
		var ldot=str.indexOf(dot)
		if (str.indexOf(at)==-1){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(at)==-1 || str.indexOf(at)==0 || str.indexOf(at)==lstr){
		   alert("Invalid E-mail Address")
		   return false
		}

		if (str.indexOf(dot)==-1 || str.indexOf(dot)==0 || str.indexOf(dot)==lstr){
		    alert("Invalid E-mail Address")
		    return false
		}

		 if (str.indexOf(at,(lat+1))!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.substring(lat-1,lat)==dot || str.substring(lat+1,lat+2)==dot){
		    alert("Invalid E-mail Address")
		    return false
		 }

		 if (str.indexOf(dot,(lat+2))==-1){
		    alert("Invalid E-mail Address")
		    return false
		 }
		
		 if (str.indexOf(" ")!=-1){
		    alert("Invalid E-mail Address")
		    return false
		 }

 		 return true					
	}

function checkall() {
  var check = true;
  var num = document.form1.item_count.value;
  for(i = 0; i < num; i++) {
     eval("check = echeck(friendemail_' + i + ');");
     if(check==false) return false;
  }
  return true;
}