How do I set a field to the difference between two dates?

[laverne]

I am new to developing in ServiceNow and am struggling to set a variable 'Days To Event' to the number of days between today and the event 'start_date'.   This value needs to update every time the form is displayed or the record is queried.   The table name is 'Marketing Events'.   The date field names are 'current_date' and 'start_date'.   The variable that needs to be set is 'days_to_event'.

I have tried creating a business rule and while the syntax is correct, I get no value to display on the form.  

Any guidance you can provide as to how and where I set values to get this functionality to work would be GREATLY appreciated.   I am developing in a scoped application.

Thank You,

LaVerne Carrick

[tony_barratt]

Hi LaVerne,

These two posts may help

How to calculate Date/Time difference on client side?

Client Script Date/Time Functions

Best Regards

Tony

[Gurpreet07]

Code on following thread should do the job for you.

Re: How to get difference between two date time fields into time.

NOTE : Use onLoad client script instead of onChange.

[laverne]

Hi Gupreet;

I created the client script and the script include for AjaxDurCalc. However, when I display a record where the start_date and current_date are set, the Days 2 Event field is all zeros.

Can you please help me understand what I am doing wrong?

I appreciate your help.

Thank you…LaVerne

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The client script is as follows:

function onLoad() {

//Type appropriate comment here, and begin script below

var strt = g_form.getValue('current_date'); //<-- This field is 'calculated' using this calculation --> GlideDateTime().getDisplayValue(); ?? is this causing a problem because it is also set on load? Should I be using strt = new GideDateTime() ???

var end = g_form.getValue('start_date');

var ajax = new GlideAjax('AjaxDurCalc');

ajax.addParam('sysparm_name','durCalc');

ajax.addParam('sysparm_strt',strt);

ajax.addParam('sysparm_end',end);

//ajax.getXMLWait(); //<-- NOTE: I am in a scoped application and this function is not allowed. ?? Not sure if this is part of the problem Is there a similar call I can use in a scoped application?

var answer = ajax.getAnswer();

g_form.setValue('days_2_event', answer); //<-- The days_2_event field TYPE = DURATION

}

The AjaxDurCalc script include is as follows: It is Active and Client Callable

var AjaxDurCalc = Class.create();

AjaxDurCalc.prototype = Object.extendsObject(AbstractAjaxProcessor,

});

LaVerne Carrick

Global Inspections — Security Analyst

Policy, Risk and Oversight

PayPal Information Security

Phone: 480.862.7219

_30x123

9999 N. 90th Street

Scottsdale, AZ 85258

USA

[droid]

Hey,

Try this onLoad script, this will change the field as a difference between two dates.

function onLoad() {

        var firstDate = g_form.getValue('current_date');

        var secondDate = g_form.getValue('start_date');

        g_form.setValue('days_to_event',gs.dateDiff(firstDate,secondDate, false));   // false will return in date format, true in string

}