jquery - What does "this" refer to in the following javascript? -

disclaimer: asking specific use of this, not this used in general. so, please no google/copy/paste speed answers (:

i have javascript/jquery code below:

var req = {};  function getdata() {     var frompage = 0;     var topage = 1;      req = $.ajax({                     url: "/_vti_bin/lists.asmx",                     type: "post",                     datatype: "xml",                     data: xmldata,                     complete: onsuccess,                     error: function (xhr, ajaxoptions, thrownerror) {                         alert("error: " + xhr.statustext);                         alert(thrownerror);                     },                     contenttype: "text/xml; charset=\"utf-8\""                 });       req.frompage = frompage;      req.topage = topage; }  function onsuccess(resp) {     alert(this.frompage); } 

i find pretty confusing code using frompage in 2 places (sorry not code).

does this refer var declared inside of getdata or 1 part of req object? or maybe else entirely....

any appreciated.

according jquery.ajax documentation:

the reference within callbacks object in context option passed $.ajax in settings; if context not specified, reference ajax settings themselves.

in other words, since didn't set context option, this options object {...} passed parameter $.ajax.

the code posted seems wrong: reads frompage wrong object. work if set frompage on options object instead:

req = $.ajax({     //other options here...     frompage: frompage });