I want to read the file uploaded by users on the client side and then do processing on them, instead of doing it on server-side. Is it possible read files and do manipulation using javascript on client side. Is it possible to use VBScript for this
I want to read the file uploaded by users on the client side and then do processing on them, instead of doing it on server-side. Is it possible read files and do manipulation using javascript on client side. Is it possible to use VBScript for this
I've done some very simple xlsx parsing in the browser. See https://gist.github./3375836. Try it out at http://jsfiddle/fAKGA/2. Copied here for convenience:
/*
Relies on jQuery, underscore.js, Async.js (https://github./caolan/async), and zip.js (http://gildas-lormeau.github./zip.js).
Tested only in Chrome on OS X.
Call xlsxParser.parse(file) where file is an instance of File. For example (untested):
document.ondrop = function(e) {
var file = e.dataTransfer.files[0];
excelParser.parse(file).then(function(data) {
console.log(data);
}, function(err) {
console.log('error', err);
});
}
*/
xlsxParser = (function() {
function extractFiles(file) {
var deferred = $.Deferred();
zip.createReader(new zip.BlobReader(file), function(reader) {
reader.getEntries(function(entries) {
async.reduce(entries, {}, function(memo, entry, done) {
var files = ['xl/worksheets/sheet1.xml', 'xl/sharedStrings.xml'];
if (files.indexOf(entry.filename) == -1) return done(null, memo);
entry.getData(new zip.TextWriter(), function(data) {
memo[entry.filename.split('/').pop()] = data;
done(null, memo);
});
}, function(err, files) {
if (err) deferred.reject(err);
else deferred.resolve(files);
});
});
}, function(error) { deferred.reject(error); });
return deferred.promise();
}
function extractData(files) {
var sheet = $(files['sheet1.xml']),
strings = $(files['sharedStrings.xml']),
data = [];
var colToInt = function(col) {
var letters = ["", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
var col = $.trim(col).split('');
var n = 0;
for (var i = 0; i < col.length; i++) {
n *= 26;
n += letters.indexOf(col[i]);
}
return n;
};
var Cell = function(cell) {
cell = cell.split(/([0-9]+)/);
this.row = parseInt(cell[1]);
this.column = colToInt(cell[0]);
};
var d = sheet.find('dimension').attr('ref').split(':');
d = _.map(d, function(v) { return new Cell(v); });
var cols = d[1].column - d[0].column + 1,
rows = d[1].row - d[0].row + 1;
_(rows).times(function() {
var _row = [];
_(cols).times(function() { _row.push(''); });
data.push(_row);
});
sheet.find('sheetData row c').each(function(i, c) {
var $cell = $(c),
cell = new Cell($cell.attr('r')),
type = $cell.attr('t'),
value = $cell.find('v').text();
if (type == 's') value = strings.find('si t').eq(parseInt(value)).text();
data[cell.row - d[0].row][cell.column - d[0].column] = value;
});
return data;
}
return {
parse: function(file) {
return extractFiles(file).pipe(function(files) {
return extractData(files);
});
}
}
})();
The browser should make it impossible to access local files (and we all should be happy about that). But the user could install a .HTA that can do short of everything on the local/client puter.
In short, No. The is no way for javascript to access the filesystem, this would be a major security threat/attack vector.
Absolutely not. For security purposes, this must be done server side. I can't think of single reason you wouldn't want to do it that way anyway.