This is easier to do in IE than other browsers because IE's TextRange objects have an execCommand() method, meaning that a command can be executed on a section of the document without needing to change the selection and temporarily enable designMode (which is what you have to do in other browsers). Here's a function to do what you want cleanly:

function execCommandOnElement(el, commandName, value) {

    if (typeof value == undefined) {

        value = null;

    }



    if (typeof window.getSelection != undefined) {

        // Non-IE case

        var sel = window.getSelection();



        // Save the current selection

        var savedRanges = [];

        for (var i = 0, len = sel.rangeCount; i < len; ++i) {

            savedRanges[i] = sel.getRangeAt(i).cloneRange();

        }



        // Temporarily enable designMode so that

        // document.execCommand() will work

        document.designMode = on;



        // Select the element's content

        sel = window.getSelection();

        var range = document.createRange();

        range.selectNodeContents(el);

        sel.removeAllRanges();

        sel.addRange(range);



        // Execute the command

        document.execCommand(commandName, false, value);



        // Disable designMode

        document.designMode = off;



        // Restore the previous selection

        sel = window.getSelection();

        sel.removeAllRanges();

        for (var i = 0, len = savedRanges.length; i < len; ++i) {

            sel.addRange(savedRanges[i]);

        }

    } else if (typeof document.body.createTextRange != undefined) {

        // IE case

        var textRange = document.body.createTextRange();

        textRange.moveToElementText(el);

        textRange.execCommand(commandName, false, value);

    }

}

Examples:

var testDiv = document.getElementById(test);

execCommandOnElement(testDiv, Bold);

execCommandOnElement(testDiv, ForeColor, red);