WEB安全之防范XSS

HTML编码

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; //newline
            case 32: return "&nbsp;"; break; //space
            case 34:return "&quot;"; break; //"
            case 38:return "&amp;"; break; //&
            case 39:return "&#x27;"; break; //'
            case 47:return "&#x2F;"; 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;
            }
        }
    }
}

参见 xss.js

https://www.bootcdn.cn/js-xss/