How to connect to SQL Server database from JavaScript in the browser?

Web services

SQL 2005+ supports native WebServices that you could almost use although I wouldn't suggest it, because of security risks you may face. Why did I say almost. Well Javascript is not SOAP native, so it would be a bit more complicated to actually make it. You'd have to send and receive SOAP via XmlHttpRequest. Check google for Javascript SOAP clients.

• http://msdn.microsoft.com/en-us/library/ms345123.aspx - SQL native WebServices
• http://www.google.com/search?q=javascript+soap - Google results for Javascript SOAP clients

A perfect working code..

    <script>
    var objConnection = new ActiveXObject("adodb.connection");
    var strConn = "driver={sql server};server=QITBLRQIPL030;database=adventureworks;uid=sa;password=12345";
    objConnection.Open(strConn);
    var rs = new ActiveXObject("ADODB.Recordset");
    var strQuery = "SELECT * FROM  Person.Address";
    rs.Open(strQuery, objConnection);
    rs.MoveFirst();
    while (!rs.EOF) {
        document.write(rs.fields(0) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;");
        document.write(rs.fields(1) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;");
        document.write(rs.fields(2) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;    ");
        document.write(rs.fields(3) + "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;    ");
        document.write(rs.fields(4) + "<br/>");
        rs.movenext();
    }
</script>

You shouldn´t use client javascript to access databases for several reasons (bad practice, security issues, etc) but if you really want to do this, here is an example:

var connection = new ActiveXObject("ADODB.Connection") ;

var connectionstring="Data Source=<server>;Initial Catalog=<catalog>;User ID=<user>;Password=<password>;Provider=SQLOLEDB";

connection.Open(connectionstring);
var rs = new ActiveXObject("ADODB.Recordset");

rs.Open("SELECT * FROM table", connection);
rs.MoveFirst
while(!rs.eof)
{
   document.write(rs.fields(1));
   rs.movenext;
}

rs.close;
connection.close; 

A better way to connect to a sql server would be to use some server side language like PHP, Java, .NET, among others. Client javascript should be used only for the interfaces.

And there are rumors of an ancient legend about the existence of server javascript, but this is another story. ;)

This would be really bad to do because sharing your connection string opens up your website to so many vulnerabilities that you can't simply patch up, you have to use a different method if you want it to be secure. Otherwise you are opening up to a huge audience to take advantage of your site.