如何从IE中的Javascript访问XHR responseBody（用于二进制数据）？

是的，我想通过IE中的XHR读取二进制数据的答案是使用VBscript注入。一开始这对我来说很令人讨厌，但是，我将其视为仅仅是一个依赖于浏览器的代码。（常规XHR和responseText在其他浏览器中可以正常工作；您可能必须使用来强制MIME类型。IE

XMLHttpRequest.overrideMimeType()

这就是我得到的东西

responseText

if(/msie/i.test(navigator.userAgent) && !/opera/i.test(navigator.userAgent)) {    var IEBinaryToArray_ByteStr_script =    "<!-- IEBinaryToArray_ByteStr -->rn"+    "<script type='text/vbscript' language='VBscript'>rn"+    "Function IEBinaryToArray_ByteStr(Binary)rn"+    "   IEBinaryToArray_ByteStr = CStr(Binary)rn"+    "End Functionrn"+    "Function IEBinaryToArray_ByteStr_Last(Binary)rn"+    "   Dim lastIndexrn"+    "   lastIndex = LenB(Binary)rn"+    "   if lastIndex mod 2 Thenrn"+    "       IEBinaryToArray_ByteStr_Last = Chr( AscB( MidB( Binary, lastIndex, 1 ) ) )rn"+    "   Elsern"+    "       IEBinaryToArray_ByteStr_Last = "+'""'+"rn"+    "   End Ifrn"+    "End Functionrn"+    "</script>rn";    // inject VBscript    document.write(IEBinaryToArray_ByteStr_script);}

我正在使用的读取二进制文件的JS类公开了一个有趣的方法

readCharAt(i)

// see doc on http://msdn.microsoft.com/en-us/library/ms535874(VS.85).aspxfunction getXMLHttpRequest() {    if (window.XMLHttpRequest) {        return new window.XMLHttpRequest;    }    else {        try { return new ActiveXObject("MSXML2.XMLHTTP");         }        catch(ex) { return null;        }    }}// this fn is invoked if IEfunction IeBinFileReaderImpl(fileURL){    this.req = getXMLHttpRequest();    this.req.open("GET", fileURL, true);    this.req.setRequestHeader("Accept-Charset", "x-user-defined");    // my helper to convert from responseBody to a "responseText" like thing    var convertResponseBodyToText = function (binary) {        var byteMapping = {};        for ( var i = 0; i < 256; i++ ) { for ( var j = 0; j < 256; j++ ) {     byteMapping[ String.fromCharCode( i + j * 256 ) ] =         String.fromCharCode(i) + String.fromCharCode(j); }        }        // call into VBscript utility fns        var rawBytes = IEBinaryToArray_ByteStr(binary);        var lastChr = IEBinaryToArray_ByteStr_Last(binary);        return rawBytes.replace(/[sS]/g,          function( match ) { return byteMapping[match]; }) + lastChr;    };    this.req.onreadystatechange = function(event){        if (that.req.readyState == 4) { that.status = "Status: " + that.req.status; //that.httpStatus = that.req.status; if (that.req.status == 200) {     // this doesn't work     //fileContents = that.req.responseBody.toArray();     // this doesn't work     //fileContents = new VBArray(that.req.responseBody).toArray();     // this works...     var fileContents = convertResponseBodyToText(that.req.responseBody);     fileSize = fileContents.length-1;     if(that.fileSize < 0) throwException(_exception.FileLoadFailed);     that.readByteAt = function(i){         return fileContents.charCodeAt(i) & 0xff;     }; } if (typeof callback == "function"){ callback(that);}        }    };    this.req.send();}// this fn is invoked if non IEfunction NormalBinFileReaderImpl(fileURL){    this.req = new XMLHttpRequest();    this.req.open('GET', fileURL, true);    this.req.onreadystatechange = function(aEvt) {        if (that.req.readyState == 4) { if(that.req.status == 200){     var fileContents = that.req.responseText;     fileSize = fileContents.length;     that.readByteAt = function(i){         return fileContents.charCodeAt(i) & 0xff;     }     if (typeof callback == "function"){ callback(that);} } else     throwException(_exception.FileLoadFailed);        }    };    //XHR binary charset opt by Marcus Granado 2006 [http://mgran.blogspot.com]     this.req.overrideMimeType('text/plain; charset=x-user-defined');    this.req.send(null);}

转换码被提供Miskun。

效果很好。

我使用此方法从Javascript读取和提取zip文件，并且还在使用Javascript读取和显示EPUB文件的类中使用了该方法。性能非常合理。500kb文件大约需要半秒钟。