This one tripped me up and it took me a while to pin down what the problem was. Turns out the variable name “class” is reserved in IE but not in other browsers (Firefox/Chrome).
My code used a variable to insert a css class onto an element, something like:
var class = "blue"; element.innerHTML = "<span class='" + class + "'>comment</span>";
I think this is because IE allows you to reference the css class of an object through this attribute, rather than using the “className” attribute.
I guess this is another example of IE trying to make our lives “more compatible” but actually making it hard work for everyone.
I also discovered IE8′s new debugger during this time though which actually tells you where your JS errors lie, rather than just saying “Line 1 character 2342″.
Finally something to make a developer’s life easier in IE!