How to have a post method with some parameters and get back successful response from server

I am trying this to get json object but it does not seem to work

$.post("/csm/compare.action",
          { 
            sessiontoken: sessiontoken,
            compareCategory: "system",
            compareSubCategory:"patch",
            xml1:absP[0],
            xml2:absP[1]},
              function(data)
              {


                alert(data.response[0].elementName);
}
        );

Part of my json that gets returned

{
"response": [
    {
        "id": "0",
        "elementName": "Accounting.ACCT-ENG-A-MAN",
        "subCategory": "patch",
        "isEqual": false,
        "isPrasentinXml1": true,
        "isPrasentinXml2": true,
        "attribute": [
            {
                "name": "information",
                "firstValue": "Acco",
                "secondValue": "Acco"
            },
            {
                "name": "name",
                "firstValue"开发者_如何学C: "Accounting.ACCT-ENG-A-MAN",
                "secondValue": "Accounting.ACCT-ENG-A-MAN"
            },
            {
                "name": "version",
                "firstValue": "B.11.23",
                "secondValue": "B.11.23"
            }
        ]
    }
]
}

try

$.post("/csm/compare.action",
          { 
            sessiontoken: sessiontoken,
            compareCategory: "system",
            compareSubCategory:"patch",
            xml1:absP[0],
            xml2:absP[1]},
              function(data)
              {
                data = $.parseJSON(data);

                alert(data.response[0].elementName);
}
        );

 $.post('"/csm/compare.action"',
 { 
            sessiontoken: sessiontoken,
            compareCategory: "system",
            compareSubCategory:"patch",
            xml1:absP[0],
            xml2:absP[1]},
            function(data){
                alert(data);
                alert(data.response[0].elementName);
            }, 'json');

not sure whether it'll help or not but you can try it anyway also if you use $.ajax instead of post you can make an error call back that will give a more insight

try this if the above fails

$.post("/csm/compare.action",
          { 
            sessiontoken: sessiontoken,
            compareCategory: "system",
            compareSubCategory:"patch",
            xml1:absP[0],
            xml2:absP[1]},
              function(data)
              {
                data = JSON.parse(data);   <-- the change is here
                alert(data);
                alert(data.response[0].elementName);
}
        );

the ajax equivalent is

$.ajax({

url:'/csm/compare.action',
type:'POST',
data:{
        sessiontoken: sessiontoken,
        compareCategory: "system",
        compareSubCategory:"patch",
        xml1:absP[0],
        xml2:absP[1]
},
cache:false,
success:function(data){
data = JSON.parse(data);
alert(data);
},
error:function(jqxhr){
alert(jqxhr.status);
alert(jqxhr.responseText);
}

});