help with cursor positioning!

**maltomeal8** · Aug 22, 2003, 15:30

I am trying to write a calculator in the browser, and one of the pieces of it is to highlight the syntax as the user types. I have some sample code here, which highlights the first 5 characters you type as red, and all the rest as blue (stupid test, but I couldn't come up with anything good and simple).

My problem is that the cursor position is lost. For example, type "Hello World" then click before the W to position the cursor there. Now type another character, and you will see that the cursor is moved to the end.

I have some code I commented out below which was my attempt to fix this, but it doesn't work (it highlights all the text instead).

Please note: I only care about IE 6.

here's my sample code:
<html>
<script>

function SyntaxHighlight()
{
var strText = document.all.divElement.innerText;
if(strText.length < 5) return;

var strVal = strText.substring(0,5).fontcolor("red");
strVal += strText.substring(5, strText.length).fontcolor("blue");

//var oCursorPos = document.selection.createRange().duplicate();
document.all.divElement.innerHTML = strVal;
//oCursorPos.select();
}

</script>

<body>
<div onkeyup="SyntaxHighlight()"
id="divElement" contenteditable="true" style="border:2px solid black;height:90%;width:340px;">
</div>
</body>

</html>

help is much appreciated!

**Arkkimaagi** · Aug 23, 2003, 06:47

Huh, this is a tough one, I searched for a while and did not find any good samples on createRange() usage with divs. Adding stuff inbetween there works, but manipulating the whole content and then selecting the previous place seems to be hard.

Sorry, I used an hour on this, but could not find a solution, lets hope someone with more skills can help you.

**maltomeal8** · Aug 28, 2003, 11:50

Hmm... I wonder if it's not possible then... seems like nobody knows the answer

**Vincent Puglia** · Aug 28, 2003, 12:43

Hi,

A 'possible' quick fix:

Code:

if (event.keyCode == 32) // code for 'space'
{
var strVal = strText.substring(0,5).fontcolor("red" );
strVal += strText.substring(5, strText.length).fontcolor("blue" );

document.all.divElement.innerHTML = strVal;
}

The above will prevent the cursor from jumping until a 'space' is used. It also prevents color coding until then.

If I have time, I'll come up with a better solution.

Vinny

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