Text to HTML char entities.
function toCharEntity(str, useHexa) {
if (str !== undefined && str !== null) {
str = '' + str;
var codeCache;
var res = '';
for(var i = 0, l = str.length; i < l ;) {
res += '&#';
codeCache = str.charCodeAt(i++);
res += useHexa ? 'x' + codeCache.toString('16') : codeCache;
res += ';';
}
return res;
}
}