If we use the jquery ajax api, it an asynchronism by default, most of time this is what we need, but in some special case we will want to make a synchronized ajax call.

For make a synchronized ajax call, we can use ‘async: false‘ setting, it will disable async for handle the return value. For example:

and we can check the return value with ‘jqXHR.responseJSON‘, so we can create a function for that:

function syncAjax(url, data){
  var jqXHR = $.ajax({
    url: url,
    type: 'POST',
    async: false,
    data: data
  });
  return jqXHR.responseJSON
}

use the function as below:

var result = syncAjax('http://www.abc.com/checkExists',{
  orderNo: '00001'
});

if(result.isExist){ //this is the server side value for return
  //to do...
}