<telerik:RadAsyncUpload runat="server" ID="rau1"></telerik:RadAsyncUpload>
<script>
	Telerik.Web.UI.RadAsyncUpload.Modules.FileApi.uploadRequest.prototype.writeFormData = function (isLastChunk) {
		this.formData.append("rauPostData", this.moduleContext.upload.postData);
		var currentChunk = this.context.get_currentChunk(),
			module = this.moduleContext.module,
			row = this.context.row;

		if ($telerik.isIE10 && this.context.file.size == 0) {
			var ua = window.navigator.userAgent; // the bug is only in IE10 browser, under IE11 modeIE10 the issue does not exists.

			if (ua.indexOf("Trident/7.0") == -1) {

				module.trigger("FileUploadFail", row, "IE10 browser does not support upload of 0 bytes size file");
				module._uploadNextFile(uploadRows[rowsLookup[row.id]]);
				module._marshalHoldContext();

				return true;
			}
		}

		if ($telerik.isOpera) {
			this.formData.append("file", currentChunk, "blob");
		}
		else {
			this.formData.append("file", currentChunk, this.context.file.name);
		}
		if (isLastChunk) {
			this.formData.append("fileName", this.context.file.name);
			this.formData.append("contentType", this.context.file.type);
			if (this.context.file.lastModifiedDate)
				this.formData.append("lastModifiedDate", this.context.file.lastModifiedDate.toJSON());
		}

		var serializedMetaData = JSON.stringify(this.context.metaData);
		if (this.context.get_chunker() /* supports chunking */ && this.context.file.size > 0)
			this.formData.append("metadata", serializedMetaData);
		else if (this.context.file.size == 0)
			this.formData.append("metadata", serializedMetaData);
	}
</script>