为什么我不能使用javascript进行正确的SQL / PHP查询？

I am trying to make a query to an SQL database and I can't figure out why my code won't work. When I call the javascript function:

function calledfunction(){
var date = new Date(document.getElementById("datetime1").value);
var dateformat = "'"+date.getFullYear() + "-" + (date.getMonth()+1) + "-" + date.getDate() + " " + date.getHours() +":" + date.getMinutes()+"'";
        alert("Value is: " + dateformat);
                microAjax("genjsonphp.php?stdt="+dateformat, function(data) {
                     //edited out
      }

I get the alert: Value is: '2011-12-6 0:0'

When I copy the value in the alert and paste it so the above code becomes:

function calledfunction(){
var date = new Date(document.getElementById("datetime1").value);
var dateformat = "'"+date.getFullYear() + "-" + (date.getMonth()+1) + "-" + date.getDate() + " " + date.getHours() +":" + date.getMinutes()+"'";
        alert("Value is: " + dateformat);
dateformat = '2011-12-6 0:0';

                microAjax("genjsonphp.php?stdt="+dateformat, function(data) {
                     //edited out
      }

Then the code works fine. Does anyone have an idea what is going wrong?

You're explicitly quoting the variable string:

 "'"+date.getFullYear() ...

so you're sending

genjsonphp.php?stdt='2011-12-6 0:0'

(note the single quotes)

In the second case you're sending:

genjsonphp.php?stdt=2011-12-6 0:0

this "genjsonphp.php?stdt="+'2011-12-6 0:0' parses to: "genjsonphp.php?stdt=2011-12-6 0:0" while "genjsonphp.php?stdt="+dateformat parses to: "genjsonphp.php?stdt='2011-12-6 0:0'"

Watch the quotes.