AJAX and php POST problems - php

Question

I am trying to pass to a PHP file cellnumber. My AJAX isn't even working, when I try
alert("test"); in the ajax.onreadystatefunction() it won't print.
My javascript getrow(t) function gets called every time someone clicks on a cell in a table
and the result is the cell turning into green. I want to ultimately enter this data into a postgres table using php.
Thanks for all the help!
Vlad
<script type="text/javascript">
//gets the row and column number
function getRow(t)
{
var col=t.cellIndex;
var row=t.parentNode.rowIndex;
var testTable = document.getElementById("testTable");
t.style.backgroundColor = "#33CC66";
var cellnumber = (row*15 + col);
var ajax = new XMLHttpRequest();
//use ajax to enter into visitedCells
ajax.onreadystatechange = function()
{
// Call a function when the state changes.
if(ajax.readyState == 4 && ajax.status == 200)
{
ajax.open("POST", insertCoordinates.php, true);
ajax.send(cellnumber);
}
else
{
alert("Error:" + ajax.status + "and " + ajax.statusText);
}
}
}
</script>
</body>
</html>

Answer 1

ajax.open("POST", insertCoordinates.php, true);
ajax.send(cellnumber);
should be outside ajax.onreadystatechange
just befor }//getRow
you actually don't have the request executed
should be like that:
var ajax = new XMLHttpRequest();
//use ajax to enter into visitedCells
ajax.onreadystatechange = function() {//Call a function when the state changes.
if(ajax.readyState == 4 && ajax.status == 200) {
alert('success');
} else {
alert("Error:" + ajax.status + "and " + ajax.statusText);
}
}//onreadyState
ajax.open("POST", insertCoordinates.php, true);
ajax.send(cellnumber);
probably won't work in IE
should use a construction like that:
try{
// Opera 8.0+, Firefox, Safari
ajaxRequest = new XMLHttpRequest();
} catch (e){
// Internet Explorer Browsers
try{
ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try{
ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e){
// Something went wrong
alert("Your browser broke!");
return false;
}
}
}
but the best way is to use jQuery ...easy and safe