function cs(address) {
    if ((address == "")
    || (address.indexOf ('@') == -1)
    || (address.indexOf ('.') == -1))

  return false;
  return true;
}

function cs1() {
  var c1,c2,c3,c4,c;
  validity = true; 
  if (!cs(document.cstj.lz.value))
     { validity = false; alert('E-mail没输或错输！');}
  if (validity)
  	c1="------------------------------------------------------------------------------------------------";
	c2="        您好! 向您推荐一篇来自\"星辰在线\"网站的文章，标题是： “"+document.title+"”";
	c3="        网址为：“"+this.location+"”";
	c4="---------------------------------------------------------------------------------------------------"+"\n";	
	c=c1+"\n"+c2+"\n"+c3+"\n"+c4+"\n";
	document.cstj.ID.value=c;
	document.cstj.action="mailto:"+document.cstj.lz.value+"?\&";
 
  return validity;
}