Test your nerves

<p>Test your Response time!</p>
Click on "Start" first, and wait until the background color changes. As soon as it changes, hit "stop!"

<script language="JavaScript">
<!--

//Reflext Tester- By Andy Scott (based on script by Jasper van Zandbeek)

var startTime=new Date();
var endTime=new Date();
var startPressed=false;
var bgChangeStarted=false;
var maxWait=20;
var timerID;


var colors=new Array("tomato","chocolate","limegreen","crimson","darkslategray",
"aliceblue","mediumslateblue","cornflowerblue","darkorchid","darkkhaki","coral",
"darkolivegreen","cadetblue")

if (document.all||document.getElementById)
document.write('<div id="reflex" style="width:135px;height:135px;border:1px solid black" onClick="stopTest()"></div>')

function startTest()
{
if (document.all)
document.all.reflex.style.backgroundColor=colors[Math.floor(Math.random()*colors.length)];
else if (document.getElementById)
document.getElementById("reflex").style.backgroundColor=colors[Math.floor(Math.random()*colors.length)];
else if (document.layers)
document.reflexns.document.reflexns_sub.document.bgColor=colors[Math.floor(Math.random()*colors.length)];
bgChangeStarted=true;
startTime=new Date();
}

function remark(responseTime)
{
var responseString="";
if (responseTime < 0.10)
responseString="Well done!";
if (responseTime >= 0.10 && responseTime < 0.20)
responseString="Nice!";
if (responseTime >=0.20 && responseTime < 0.30)
responseString="Could be better...";
if (responseTime >=0.30 && responseTime < 0.60)
responseString="Keep practising!";
if (responseTime >=0.60 && responseTime < 1)
responseString="Have you been drinking?";
if (responseTime >=1)
responseString="Did you fall asleep?";

return responseString;
}

function stopTest()
{
if(bgChangeStarted)
{
endTime=new Date();
var responseTime=(endTime.getTime()-startTime.getTime())/1000;
if (document.all)
document.all.reflex.style.backgroundColor="white";
else if (document.getElementById)
document.getElementById("reflex").style.backgroundColor="white";
else if (document.layers)
document.reflexns.document.reflexns_sub.document.bgColor="white";
alert("Your response time is: " + responseTime + " seconds " + "\n" + remark(responseTime));
startPressed=false;
bgChangeStarted=false;
}
else
{
if (!startPressed)
{
alert("press start first to start test");
}
else
{
clearTimeout(timerID);
startPressed=false;
alert("cheater! you pressed too early!");
}
}
}

var randMULTIPLIER=0x015a4e35;
var randINCREMENT=1;
var today=new Date();
var randSeed=today.getSeconds();
function randNumber()
{
randSeed = (randMULTIPLIER * randSeed + randINCREMENT) % (1 << 31);
return((randSeed >> 15) & 0x7fff) / 32767;
}

function startit()
{
if(startPressed)
{
alert("Already started. Press stop to stop");
return;
}
else
{
startPressed=true;
timerID=setTimeout('startTest()', 6000*randNumber());
}
}
// -->
</script>
<br>


<ilayer id="reflexns" width=135; height=135;><layer id="reflexns_sub" width=135; height=135; left=0 top=0 bgColor=yellow></layer></ilayer>

<form name="response">

<input type="button" value=" start " onClick="startit()" style="font-weight:bold">
<input type="button" value=" stop " onClick="stopTest()" style="font-weight:bold">
</form>