//使用“\”对特殊字符进行转义，除数字字母之外，小于127使用16进制“\xHH”的方式进行编码，大于用unicode（非常严格模式）。
var JavaScriptEncode = function(str){var hex=new Array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f');function changeTo16Hex(charCode){return "\\x" + charCode.charCodeAt(0).toString(16);}function encodeCharx(original) {var found = true;var thecharchar = original.charAt(0);var thechar = original.charCodeAt(0);switch(thecharchar) {case '\n': return "\\n"; break; //newlinecase '\r': return "\\r"; break; //Carriage returncase '\'': return "\\'"; break;case '"': return "\\\""; break;case '\&': return "\\&"; break;case '\\': return "\\\\"; break;case '\t': return "\\t"; break;case '\b': return "\\b"; break;case '\f': return "\\f"; break;case '/': return "\\x2F"; break;case '<': return "\\x3C"; break;case '>': return "\\x3E"; break;default:found=false;break;}if(!found){if(thechar > 47 && thechar < 58){ //数字return original;}if(thechar > 64 && thechar < 91){ //大写字母return original;}if(thechar > 96 && thechar < 123){ //小写字母return original;}        if(thechar>127) { //大于127用unicodevar c = thechar;var a4 = c%16;c = Math.floor(c/16); var a3 = c%16;c = Math.floor(c/16);var a2 = c%16;c = Math.floor(c/16);var a1 = c%16;return "\\u"+hex[a1]+hex[a2]+hex[a3]+hex[a4]+"";        }else {return changeTo16Hex(original);}}}     var preescape = str;var escaped = "";var i=0;for(i=0; i < preescape.length; i++){escaped = escaped + encodeCharx(preescape.charAt(i));}return escaped;
}

var HtmlEncode = function(str){var hex = new Array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f');var preescape = str;var escaped = "";for(var i = 0; i < preescape.length; i++){var p = preescape.charAt(i);escaped = escaped + escapeCharx(p);}return escaped;function escapeCharx(original){var found=true;var thechar=original.charCodeAt(0);switch(thechar) {case 10: return "<br/>"; break; //newlinecase 32: return "&nbsp;"; break; //spacecase 34:return "&quot;"; break; //"case 38:return "&amp;"; break; //&case 39:return "'"; break; //'case 47:return "/"; break; // /case 60:return "&lt;"; break; //<case 62:return "&gt;"; break; //>case 198:return "&AElig;"; break;case 193:return "&Aacute;"; break;case 194:return "&Acirc;"; break; case 192:return "&Agrave;"; break; case 197:return "&Aring;"; break; case 195:return "&Atilde;"; break; case 196:return "&Auml;"; break; case 199:return "&Ccedil;"; break; case 208:return "&ETH;"; break;case 201:return "&Eacute;"; break; case 202:return "&Ecirc;"; break; case 200:return "&Egrave;"; break; case 203:return "&Euml;"; break;case 205:return "&Iacute;"; break;case 206:return "&Icirc;"; break; case 204:return "&Igrave;"; break; case 207:return "&Iuml;"; break;case 209:return "&Ntilde;"; break; case 211:return "&Oacute;"; break;case 212:return "&Ocirc;"; break; case 210:return "&Ograve;"; break; case 216:return "&Oslash;"; break; case 213:return "&Otilde;"; break; case 214:return "&Ouml;"; break;case 222:return "&THORN;"; break; case 218:return "&Uacute;"; break; case 219:return "&Ucirc;"; break; case 217:return "&Ugrave;"; break; case 220:return "&Uuml;"; break; case 221:return "&Yacute;"; break;case 225:return "&aacute;"; break; case 226:return "&acirc;"; break; case 230:return "&aelig;"; break; case 224:return "&agrave;"; break; case 229:return "&aring;"; break; case 227:return "&atilde;"; break; case 228:return "&auml;"; break; case 231:return "&ccedil;"; break; case 233:return "&eacute;"; break;case 234:return "&ecirc;"; break; case 232:return "&egrave;"; break; case 240:return "&eth;"; break; case 235:return "&euml;"; break; case 237:return "&iacute;"; break; case 238:return "&icirc;"; break; case 236:return "&igrave;"; break; case 239:return "&iuml;"; break; case 241:return "&ntilde;"; break; case 243:return "&oacute;"; break;case 244:return "&ocirc;"; break; case 242:return "&ograve;"; break; case 248:return "&oslash;"; break; case 245:return "&otilde;"; break;case 246:return "&ouml;"; break; case 223:return "&szlig;"; break; case 254:return "&thorn;"; break; case 250:return "&uacute;"; break; case 251:return "&ucirc;"; break; case 249:return "&ugrave;"; break; case 252:return "&uuml;"; break; case 253:return "&yacute;"; break; case 255:return "&yuml;"; break;case 162:return "&cent;"; break; case '\r': break;default:found=false;break;}if(!found){if(thechar>127) {var c=thechar;var a4=c%16;c=Math.floor(c/16); var a3=c%16;c=Math.floor(c/16);var a2=c%16;c=Math.floor(c/16);var a1=c%16;return "&#x"+hex[a1]+hex[a2]+hex[a3]+hex[a4]+";";        }else{return original;}}    }
}

<button onclick='alert("1\x29\x3balert\x282\u54c8\u54c8\x29")'>测试JavaScriptEncode值</button>
<div>&lt;script&gt;alert('1哈哈'&nbsp;/);&lt;/script&gt;</div>

var HtmlUtil = {htmlEncode:function (html){var temp = document.createElement ("div");(temp.textContent != undefined ) ? (temp.textContent = html) : (temp.innerText = html);var output = temp.innerHTML;temp = null;return output;},htmlDecode:function (text){var temp = document.createElement("div");temp.innerHTML = text;var output = temp.innerText || temp.textContent;temp = null;return output;},htmlEncodeByRegExp:function (str){var s = "";if(str.length == 0) return "";s = str.replace(/&/g,"&amp;");s = s.replace(/</g,"&lt;");s = s.replace(/>/g,"&gt;");s = s.replace(/ /g,"&nbsp;");s = s.replace(/\'/g,"'");s = s.replace(/\"/g,"&quot;");return s;},htmlDecodeByRegExp:function (str){var s = "";if(str.length == 0) return "";s = str.replace(/&amp;/g,"&");s = s.replace(/&lt;/g,"<");s = s.replace(/&gt;/g,">");s = s.replace(/&nbsp;/g," ");s = s.replace(/'/g,"\'");s = s.replace(/&quot;/g,"\"");return s;}
};

转自：http://www.cnblogs.com/lovesong/p/5211667.html