Client side Date format issueDescription<!-- div.margin{ padding: 10px 40px 40px 30px; } table.tocTable{ border: 1px solid; border-color:#E0E0E0; background-color: rgb(245, 245, 245); padding-top: .6em; padding-bottom: .6em; padding-left: .9em; padding-right: .6em; } table.noteTable{ border:1px solid; border-color:#E0E0E0; background-color: rgb(245, 245, 245); width: 100%; border-spacing:2; } table.internaltable { white-space:nowrap; text-align:left; border-width: 1px; border-collapse: collapse; font-size:14px; width: 85%; } table.internaltable th { border-width: 1px; padding: 5px; border-style: solid; border-color: rgb(245, 245, 245); background-color: rgb(245, 245, 245); } table.internaltable td { border-width: 1px; padding: 5px; border-style: solid; border-color: #E0E0E0; color: #000000; } .title { color: #D1232B; font-weight:normal; font-size:28px; } h1{ color: #D1232B; font-weight:normal; font-size:21px; margin-bottom:-5px } h2{ color: #646464; font-weight:bold; font-size:18px; } h3{ color: #000000; font-weight:BOLD; font-size:16px; text-decoration:underline; } h4{ color: #646464; font-weight:BOLD; font-size:15px; text-decoration:; } h5{ color: #000000; font-weight:BOLD; font-size:13px; text-decoration:; } h6{ color: #000000; font-weight:BOLD; font-size:14px; text-decoration:; } ul{ list-style: disc outside none; margin-left: 0; } li { padding-left: 1em; } --> Client script date validation may return as invalid when the system property glide.sys.date.format is changed from 'yyyy-MM-dd' to 'dd-MM-yyyy'. E.g: A date such as 22/04/2018 returns as invalid when the system property above is in 'dd-MM-yyyy' format, but the same date is valid when in 'yyyy-MM-dd' format. CauseProcedure to confirm the issue From sys_properties confirm/set the property 'glide.sys.date.format' value is 'yyyy-MM-dd' format.Configure the incident form layout to show 'Actual Start' field, which is of 'glide date time' field type. Then set/pick the Actual Start date eg: '22/04/2018', save the incident record.Add an onLoad client script to the incident form with the following script function onLoad() { //Type appropriate comment here, and begin script below var StartDate = new Date(g_form.getValue('work_start')); if(StartDate == 'Invalid Date' || StartDate == 'NaN'){ alert('Invalid Start Date'); }else { alert('Actual Start Date is: ' + StartDate); } } 4. Open the incident record where you added the 'Actual Start' date in step 1, you should notice an alert message reading "Actual Start Date is: Sun Apr 22 2018 xx:xx:xx". 5. Now go back to the system properties and change the property value to 'dd-MM-yyyy'. 6. Reload the same incident record, notice the alert message reading "Invalid Start Date". ResolutionUse the getDateFromFormat function, which validates the date irrespective of the format set in the system property, to verify: Open the onLoad client script on the Incident form shown in the previous stepsReplace it with the following script which used the getDateFromFormat function function onLoad() { //Type appropriate comment here, and begin script below var date_number = getDateFromFormat(g_form.getValue('work_start'), g_user_date_time_format); var StartDate = new Date(date_number); if(StartDate == 'Invalid Date' || StartDate == 'NaN'){ alert('Invalid Start Date'); }else { alert('Actual Start Date is: ' + StartDate); } } NOTE: If you are retrieving values from date-time fields then use 'g_user_date_time_format' or if you are using just a date field then use 'g_user_date_format' as the parameter.