jquery - Ajax $.ajax is not a function -

i have jquery ajax call this:

function testindustry() {     $.ajax({         type: "get",         async: false,         url: "url inserted here",         contenttype: "application/json",         datatype: 'jsonp',         success: function(datajsonp) {             if (datajsonp.industry.indexof('manufacturing') >= 0){                 //do             }         }     }); } 

but keep getting error

typeerror: $.ajax not function (in function testindustry, line 6, col 5)

i read on stackoverflow , seems happens when ajax function called this

$.ajax()({}); 

with pair of opening , closing brackets, not using. appreciated.