Javascript error object required

Question

I'm helping to debug a website and sometimes i get this error : Object required on CWS.js line 45 character 3

// Track cursor position
var CWS_curPosX, CWS_curPosY;
document.onmousemove = CWS_MouseMove;

function CWS_MouseMove(evt)
{

if(window.Event)
{
    if(evt && evt.pageX)
    {
        CWS_curPosX = evt.pageX;
        CWS_curPosY = evt.pageY; 
    }
}
else
{
    CWS_curPosX = event.clientX + document.body.scrollLeft; // line 45
    CWS_curPosY = event.clientY + document.body.scrollTop;
}

I have no idea to solve this... Thanks in advance.

Jamiec · Accepted Answer · 2011-12-21 12:23:19Z

1

There is a couple of crucial isues with your code, primarily your use of window.Event - this if(...) condition will always evaluate false, as no browser supports this property on the window object. In actual fact the property has a lower case e in IE.

So this construct is often used, and looks similar to yours:

function someEventHandler(evt){
   if(window.event){ // Note lower case 'e' in 'event'
       // browser is IE, read properties of the event from window.event
   }
   else{
       // browser is probably some flavour of Mozilla, use the passed-in 'evt' 
       // parameter to read properties of the event
   }
}

Read this link (event object in different browsers) for more info.

This cross-browser difference is one of many reasons many people tend to use a framework such as jQuery which simplifies this event-handling code into one unified method of reading properties of the event.

answered Dec 21, 2011 at 12:23

Jamiec

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2 Comments

Gun Over a year ago

Thank you for your quick response, i try it now and i wait the tester's feedback.

Ruan Mendes Over a year ago

A much simpler way is event = event || window.event

Андрей Петров · Accepted Answer · 2011-12-21 12:10:32Z

0

replace event to evt in 2 lines
CWS_curPosX = evt.clientX + document.body.scrollLeft;
CWS_curPosY = evt.clientY + document.body.scrollTop;

answered Dec 21, 2011 at 12:10

Андрей Петров

1494 bronze badges

1 Comment

Gun Over a year ago

In case of the first comment doesn't work i will try your response, thank you for your quick response too!!!

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