Is there any way to handle this timelimit for Safari browser

We have used ajax call with "async: false" through out our web application, now in Safari browser(in Windows and Mac OS both) if response gets delayed more than 5 seconds Safari browser throws dom timeout exeption.

$.ajax({

type: "POST",

contentType: "application/json; charset=utf-8",

url: "Web method url",

data: jsonData,

async: false,

success: function (data) {

},

error: function (data) {

},

complete: function () {

}

});