解决跨域ajax

$.ajax({
		async: false,
		type: "GET",
		dataType: 'jsonp',
		jsonp: 'callback',
		jsonpCallback: 'callbackfunction',
		url: urlStr,
		data: "",
		timeout: 3000,
		contentType: "application/json;utf-8",
		success: function(msg) {
		  console.log(msg);
		}
	  });