I google'ed it and I found this. Give it a try. Also there are plenty of posts and solutions out there. Find the one that works best for you.
If you have issues with that please let me know and I can help further.
function(str){n var i = str.length,n aRet = [];nn while (i--) {n var iC = str[i].charCodeAt();n if (iC < 65 || iC > 127 || (iC>90 && iC<97)) {n aRet[i] = '&#'+iC+';';n } else {n aRet[i] = str[i];n }n }n return aRet.join(''); n },