Doctype messing with expandable iframe in firefox

when i use an xhtml doctype, the expandable iframe on a page doesnt work with firefox. it will work with ie 6,7. heres a sample code:

function adjustIFrameHeight()
{
try
{
//find the height of the internal page
var theHeight = document.getElementById('myframe').contentWindow.document.body.scrollHeight;

//change the height of the iframe
document.getElementById('myframe').style.height = theHeight + 20;
} catch(e)
{
//alert("error");
}
scroll(0, 0);
}


the iframe with a set height calls the function and expands the height to fit the content. to solve this problem and allow firefox to adjust correctly, i have to switch to a html 4.01 Transitional doctype. using a transitional doctype is the only way ive found to get it to work. does anyone have any suggestions on what i should do? thanks.

Your units are missing. CSS requires units on dimensions.


should be

wonderful, thank you. couldnt see that before