$(document).ready(function() {

var css=document.styleSheets[0];
try {

    css.addRule('.boxCheckbox','filter: progid:DXImageTransform.Microsoft.Alpha(opacity=0);');
}
catch(e) {

    css.insertRule('.boxCheckbox { -moz-opacity: 0; -khtml-opacity: 0; }', css.cssRules.length);
}

var el=document.getElementsByTagName('input');
for (var i=0; i<el.length; i++) {
    if (el[i].type.toLowerCase()=='checkbox') {
        doCheckbox(el[i]);
    }
} 


})


function doCheckbox(elem) {

    if (elem.className=='boxCheckbox' &&
        elem.parentNode.tagName.toLowerCase()=='div') {

        elem.parentNode.className='box'+(elem.checked?'Checked':'Unchecked');
    }
};