Hi, Following is a simple detection script..What im tring to achive is to make each target invisible one by one. but they become hidden all at a time..There is a logical mistake.. will you please help me ...? Thanks in advance.. <html> <body bgcolor="pink"> <script> setInterval("run()",10) function run() { for(var i=0;i<=4;i++) { oto1=document.getElementById("myOto"); oto2=document.getElementById("iki"+i); } oto1.style.posLeft+=2; oto2.style.posLeft+=1; x = ((oto1.style.posLeft >= oto2.style.posLeft) && (oto1.style.posLeft <= oto2.style.posLeft)); y = ((oto1.style.posTop >= oto2.style.posTop) && (oto1.style.posTop <= oto2.style.posTop)); if (x && y) { for(m=0;m<=4;m++) { oto=document.getElementById("iki"+m); oto.style.posLeft+=1; oto.style.visibility="hidden"; } } } </script> <input type="text" value="myCar" id="myOto"style="position:absolute;top:220;left:10;width:10;"> <input type="text" value="target1" id="iki0" style="position:absolute;top:220;left:140;width:30;background-color:red;"> <input type="text" value="target2" id="iki1" style="position:absolute;top:220;left:200;width:30;background-color:red;"> <input type="text" value="target3" id="iki2" style="position:absolute;top:220;left:260;width:30;background-color:red;"> <input type="text" value="target4" id="iki3" style="position:absolute;top:220;left:320;width:30;background-color:red;"> <input type="text" value="target5" id="iki4" style="position:absolute;top:220;left:380;width:30;background-color:red;"> </body> </html> PHP: