How to preserve cursor position

[dj12345]

i have function to make character in lowercase if a text is in uppercase

   function upperCase(x)
    {   
        try
        {
            var y=document.getElementById(x).value;
            document.getElementById(x).value=y.toLowerCase();
        }
        catch(Error)
        {
        }
    }

i am calling

<asp:TextBox ID="txtUrl" Width="450px" runat="server" Wrap="true" onkeyup="upperCase(this.id)" TextMode="MultiLine"></asp:TextBox>

but whenever i type anything withing typed text for eg. if the textbox already have string "texttexttext" n if i try to modify the middle character then on upperCase function call the the function male the character to lowercase in then cursor position goes to end of the text... so i am not able to type anything in the middle... so what is the option to preserve the cursor position at it is which was befor..

[Dormilich]

the only solution on my mind is changing the event (onchange, maybe onblur). the reason (I think) for the behaviour is that the value becomes re-written (well first deleted). maybe someone know how to position the cursor in a string.....

[acoder]

That's what I would suggest. However, if you insist on using onkeyup, have a play with this (taken from this thread).