node js : should be use alert to invoke the function?

i dont know what happen with my code..i have a Node.js that queries a MySQL db within the route and displays the result to the user. My problem is how do I run the queries and block until queries are done before redirecting the user to the page they requested? if i add alert before call,function run normally and quick response..but if alert disable the function cant return any value,the function like freeze..

this user code to request value to nodejs

function fred(){ //request function from here to fblue
    alert('fred called'); //if i disable alert,the function not return any value
    get('id', function(datmovMar) {
        var obj = JSON.parse(datmovMar);
        var items = Object.keys(obj);
        var output='';
        items.forEach(function(item) {
            output+=obj[item].something+'<br/>';
          alert(output);
        });         
    });
}

function get(id, callback) {
    $.ajax('http://localhost:8000/' + id + '/', {
        type: 'GET',
        dataType: 'json',
        success: function(data) { if ( callback ) callback(data); },
        error  : function()     { if ( callback ) callback(null); }
    });
}

and this code locate in node js

fblue(function(datmovMar){  //call function from here
        res.write(JSON.stringify(datmovMar)); 
        res.end('\n');
});     

function fblue(callback){ 
    var query = connection.query('SELECT something from table'),
        pinMarker = []; 
    query
    .on('error', function(err) {
        console.log( err );
        updateSockets( err );
    })
    .on('result', function( user ) {
        pinMarker.push( user );
    })
    .on('end',function(){
        if(connectionsArray.length) {
            jsonStringx = JSON.stringify( pinMarker );
            callback(jsonStringx);
        }
    }); 
}

i dont know why if alert disable the function cant run normally?

please help...

thanks