function urlencode( str ) {
 
 var histogram = {}, histogram_r = {}, code = 0, tmp_arr = [];
 var ret = str.toString();
 
 var replacer = function(search, replace, str) {
 var tmp_arr = [];
 tmp_arr = str.split(search);
 return tmp_arr.join(replace);
 };
 
 // The histogram is identical to the one in urldecode.
 histogram['!']   = '%21';
 histogram['%20'] = '+';
 
 // Begin with encodeURIComponent, which most resembles PHP's encoding functions
 ret = encodeURIComponent(ret);
 
 for (search in histogram) {
 replace = histogram[search];
 ret = replacer(search, replace, ret) // Custom replace. No regexing
 }
 
 // Uppercase for full PHP compatibility
 return ret.replace(/(\%([a-z0-9]{2}))/g, function(full, m1, m2) {
 return "%"+m2.toUpperCase();
 });
 
 return ret;
}