JavaScript and JQuery cheatSheet

 Check value is null or empty or undefined

function isNullOrEmpty(value) {

    if (typeof value !== "undefined" && value != "null" && value != null && value.trim() != "") {

        return false;

    } else {

        return true;

    }

}

ajax Call format

$.blockUI({css: {border: 'none', backgroundColor: 'transparent'}});
$.ajax({
    url: "${createLink(controller: '',  action: '')}",
    data: {},
    type: "POST",
    dataType: "html",
    success: function (data) {
        $.unblockUI();
    },
    error: function (xhr, status) {
        $.unblockUI();
    },
    complete: function (xhr, status) {
        $.unblockUI();
    }
});

ajax dataTypes
   dataType: "html"
   dataType: "JSON"

Loader Type in jquery
$.blockUI({css: {border: 'none', backgroundColor: 'transparent'}});
$.unblockUI();
showLoader();
hideLoader();