使用AJAX时出错

I am attempting to delete a store via AJAX. When I try to run my code, it does not run successfully. I have used the debug application in Internet Explorer, and found that rather than "objRequest.status == 200", which is what I need to run the lines of code within the if statement, I get "objRequest.status == 404" I am having a very hard time finding out what is wrong with it. Could you help me find out what I did wrong?

function DeleteStore()
{
    var objRequest = new XMLHttpRequest(); 
    var url =     "http://student.business.uab.edu/webappservice/service1.svc/DeleteStore"; 

    //Collect Customer data from web page 
    var deletestoreid = document.getElementById("deletestoreid").value;

    //Create the parameter string 
    var detelenewstore = '{"StoreID":"' + deletestoreid +'"}';

    //Checking for AJAx operation return 
    objRequest.onreadystatechange = function() 
    { 
        if (objRequest.readyState == 4 && objRequest.status == 200) //This is where the arro occurs in my debugging
        { 
            var result = JSON.parse(objRequest.responseText); 
            DeleteInfo(result); 
        } 
    } 

    //Start AJAX request 
    objRequest.open("GET", url, true);
    objRequest.send();
}

function DeleteInfo(output)
{
    if (output.WasSuccessful == 1) 
        { 
            document.getElementById("youmonster").innerHTML = "You've just     killed a perfectly innocent store! You monster!" 
        } 
    else 
        { 
            document.getElementById("youmonster").innerHTML = "Aw Snap! The     operation was not successful!" + "<br>" + output.Exception; 
        } 
}