Email validity check

PHP code:

function is_email($email){
   $x = '\d\w!\#\$%&\'*+\-/=?\^_`{|}~';    //just for clarity

   return count($email = explode('@', $email, 3)) == 2
       && strlen($email[0]) < 65
       && strlen($email[1]) < 256
       && preg_match("#^[$x]+(\.?([$x]+\.)*[$x]+)?$#", $email[0])
       && preg_match('#^(([a-z0-9]+-*)?[a-z0-9]+\.)+[a-z]{2,6}.?$#', $email[1]);
}

switch order of two records in a table

When in need to change the order of a list use a field to store the order as an int:
Change the order of the records by switching the order value between consecutive elements.

case 'orderdown':
case 'orderup':{
 //get all list and retain two elements: if moveup operation then I keep prev and current 
 //otherwise I keep current and next
 $rec_list = $this->getChildren($record->id_parent);//all records on this level
 $switch = array();
 for($i = 0; $i < count($rec_list) ; $i++){
  if($rec_list[$i]['id'] == $record['id']){
   if('orderup' == $what && $i != 0){
    //not first
    $switch[$rec_list[$i-1]['id']] = $rec_list[$i]['corder'];
    $switch[$rec_list[$i]['id']] = $rec_list[$i-1]['corder'];
    break;
   }elseif('orderdown' == $what && $i != (count($rec_list)-1)){
    //not last
    $switch[$rec_list[$i+1]['id']] = $rec_list[$i]['corder'];
    $switch[$rec_list[$i]['id']] = $rec_list[$i+1]['corder'];
    break;
   }
  }
 }
 
 //valid elements found. Switch them
 if(count($switch) > 0){
  foreach ($switch as $id=>$corder) {
   $sql = "UPDATE page SET corder=$corder WHERE id=$id";
   $result = mysql_query($sql) or die("SQL ERROR " . mysql_error() . " [$sql] on " . __FILE__ . " at line " . __LINE__);
  }
 }

Instant popup on mouseover

<STYLE TYPE="text/css">
<!--
#dek {POSITION:absolute;VISIBILITY:hidden;Z-INDEX:200;}
//-->
</STYLE>
<DIV ID="dek"></DIV>

<SCRIPT TYPE="text/javascript">
<!--

Xoffset=0;    // modify these values to ...
Yoffset= 20;    // change the popup position.

var old,skn,iex=(document.all),yyy=-1000;

var ns4=document.layers
var ns6=document.getElementById&&!document.all
var ie4=document.all

if (ns4)
skn=document.dek
else if (ns6)
skn=document.getElementById("dek").style
else if (ie4)
skn=document.all.dek.style
if(ns4)document.captureEvents(Event.MOUSEMOVE);
else{
skn.visibility="visible"
skn.display="none"
}
document.onmousemove=get_mouse;

function popup(msg,bak){
var content="<table><tr><td";

content += " bgcolor='"+bak+"'";

content += ">"+msg+"</td></tr></table>";

yyy=Yoffset;
if(ns4){skn.document.write(content);skn.document.close();skn.visibility="visible"}
if(ns6){document.getElementById("dek").innerHTML=content;skn.display=''}
if(ie4){document.all("dek").innerHTML=content;skn.display=''}
}

function get_mouse(e){
if(ns4||ns6){
 skn.left=e.pageX+Xoffset+'px';
 skn.top=e.pageY+yyy + 'px';
}else{
 if (document.documentElement){
  // IE6 +4.01
  skn.left=event.x+document.documentElement.scrollLeft+Xoffset+'px';
  skn.top=event.y+document.documentElement.scrollTop+yyy + 'px';
 }else if (document.body){
  // IE5 or DTD 3.2 
  skn.left=event.x+document.body.scrollLeft+Xoffset+'px';
  skn.top=event.y+document.body.scrollTop+yyy + 'px';
 }
}
}

function kill(){
yyy=-1000;
if(ns4){skn.visibility="hidden";}
else if (ns6||ie4)
skn.display="none"
}

//-->
</SCRIPT>

Usage:

<a href="mylinkhere.php" ONMOUSEOVER="popup('Popup text','yellow')"; ONMOUSEOUT="kill()">click here</a>

Centered popup window

function popUp(theURL, myWidth, myHeight) {
var winName = 'feedback';
var features='toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0';
//var myWidth = 290;
//var myHeight = 360;
var isCenter = 'true';
 if(window.screen)if(isCenter)if(isCenter=="true"){
   var myLeft = (screen.width-myWidth)/2;
   var myTop = (screen.height-myHeight)/2;
   features+=(features!='')?',':'';
   features+=',left='+myLeft+',top='+myTop;
 }
 var handle = window.open(theURL,winName,features+((features!='')?',':'')+'width='+myWidth+',height='+myHeight);
  handle.opener = window;
  handle.focus();
 return handle;
}