Question

From a tutorial code like this

function queryDB(tx) {
    tx.executeSql('SELECT * FROM DEMO', [], querySuccess, errorCB);
}

function querySuccess(tx, results) {

}

function errorCB(err) {
    alert("Error processing SQL: "+err.code);
}

var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
db.transaction(queryDB, errorCB); 

in db.transaction i want to pass a variable as argument to queryDB function, so the code which i think of should looks like

db.transaction(queryDB(id), errorCB);

How I can actually implement this ? Or its simply gonna work like this and my id will be passed and get in tx ?

Answer 1

Wrap it in a function again

var id = 'THEID';
db.transaction(function(){
  queryDB(id)
}, errorCB);

Note – This is assuming that you’re making the API. Some APIs / frameworks insert the required information automatically. For example

//the db.transaction method
function transaction(param, callback) {
   //do code stuff
   callback(someInternalId); //callback is the function you pass as the first parameter
}

So, if you want to pass your own data in the callback, wrap it in a function. Otherwise, the code you are using may be doing this for you automatically.