HTML 5 toggling the contenteditable attribute with javascript

enter code hereI am trying to make something editable online with a function like this

function toggle_editable (div, cssclass) {

var classToEdit = document.getElementsByClassName(cssclass)

    for (i = 0;classToEdit.length; i++) {

        if (classToEdit[i].contentEditable == false) {
            classToEdit[i].contentEditable = true ;
        }
        if (classToEdit[i].contentEditable == true) {
            classToEdit[i].contentEditable = false ;
        }
    }
}

neither of the if statements work

this works however

classToEdit.contenteditable = true; as well as this

classToEdit.contenteditable = false;

but this isn't

if (classToEdit.contenteditable == true) /or false

ideas anyone?