Reading data from sqlite using sql.js

Question

I am new with java-script, it might seems a stupid question, but I tried a lot to get the right result, but still fail... I have to read and write data in sqlite file, and I found this library which is described as a port by the developer, https://github.com/lovasoa/sql.js. Please see my code below: First, I am selecting a local file via this HTML

<input type="file" id="check" onchange="working(this.files)">

The js file behind this is:

function working(data) {
//adding database
var sql = window.SQL;
var db = new sql.Database(data);
//writing a query
//read existing table called propertystring
var query = "SELECT * FROM propertystring";
var result = db.exec(query);
console.log(result);}

I am trying to debug using Google chrome console, its saying

Uncaught Error: no such table: propertystring 

Although, I have entered in my sqlite database this table and its showing me in sqlitemen The description of table is as below:

-- Describe PROPERTYSTRING
   CREATE TABLE "propertystring" (
    "sValue" TEXT,
     "TypeID" TEXT
    )
INSERT INTO propertystring (sValue, TypeID) VALUES ("yes its working", "71")

I hope, its very simple thing and any person using sql.js can simple answer me.