Field script use cases

  • Release version: Yokohama
  • Updated March 12, 2026
  • 4 minutes to read
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    Summary of Field script use cases

    This content provides practical examples of field customization scripts in ServiceNow, useful for automating and enhancing form behavior. These scripts help users automatically populate fields, validate input, control field appearance, and manipulate date/time values. While the examples are tailored for specific instances, they offer valuable patterns that can be adapted and tested to fit your ServiceNow environment.

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    Common Use Cases and Practical Applications

    • Automatically Populate Fields: Use client scripts triggered on field changes (e.g., Subcategory on Incident) to look up related values and auto-fill fields like Short Description. This improves data consistency and speeds up form completion.
    • Disable HTML Tags in Text Fields: Server-side scripts can sanitize Description and Short Description fields by replacing potentially harmful HTML tags like <script> with non-executable text, enhancing security.
    • Trim Leading and Trailing Spaces: Scripts can clean user data by removing extra spaces in user profile fields (e.g., FirstName, LastName), ensuring clean and uniform records.
    • Field Label Customization: Client scripts can make labels flash temporarily or set them to bold, helping to draw user attention to important fields.
    • Make Fields Read-Only Based on Conditions: For example, setting fields like Incident State, Impact, Urgency, Priority, Configuration Item, and Assigned To as read-only when an incident reaches certain states. This enforces data integrity and workflow compliance.
    • Set Current Date/Time in Fields: Use GlideAjax for client-server communication to insert the current date and time into date/time fields in the proper format and timezone, avoiding manual entry errors.
    • Toggle Timer Field by Name: Client scripts can programmatically start or stop timer fields on forms, useful for tracking duration fields dynamically.
    • Modify GlideDateTime Field Values: Server-side scripts using the GlideDateTime API enable adding or subtracting time intervals (seconds, days, weeks, months, years) to date/time fields, supporting complex date manipulations.

    Why This Matters

    These scripting examples empower ServiceNow customers to automate routine tasks, enforce data validation and cleansing, improve user interface responsiveness, and maintain data accuracy. Applying these techniques can streamline processes, reduce user errors, and enhance overall platform usability.

    What to Expect

    By implementing these field scripts, you can expect:

    • Increased efficiency in form completion and data entry
    • Improved data quality and consistency
    • Enhanced user experience through dynamic field behaviors and visual cues
    • Better control over field accessibility during workflow stages
    • Accurate handling of date and time values respecting time zones

    Note: As these customizations are provided as-is without official support, thorough testing in your instance is essential before deployment.

    Common use cases for field customization scripts.

    Warning:
    The customization described here was developed for use in specific instances, and is not supported by Now Support. This method is provided as-is and should be tested thoroughly before implementation. Post all questions and comments regarding this customization to our community forum.

    For more information, see Server API reference.

    Automatically populate a field

    The following example shows how to use a client script to auto-fill a Short Description based on the selected Subcategory.

    In this case, if the table has a record with Subcategory = Password and Short Description = Password Reset. When the user selects the Subcategory of Password on the Incident form, a client script looks up the matching record and sets Short Description equal to Password Reset.

    Client script settings:
    • Type = onChange
    • Table name = incident
    • Field name = Subcategory
    function onChange(control, oldValue, newValue, isLoading){
        if(isLoading){return;}
        var newrec = gel('sys_row');
        //Check if new record
        if (newrec.value == -1) {
            var lookup = new GlideRecord('u_short_desc_lookup');
            lookup.addQuery('u_subcategory', g_form.getValue('subcategory'));
            lookup.query();
            var temp; //temp var - reusable
            if(lookup.next()){
                temp = lookup.u_short_description;
                if(null != temp) {
                    //Set the form value from lookup if there is a lookup value
                    g_form.setValue('short_description', temp);
                } else {
                    g_form.setValue('short_description',"");
                    }
              } else {
                  //If a lookup record does not exist based on lookup.addQuery
                  //Then set to UNDEFINED or NULL depending on type
                  g_form.setValue('short_description',"");
                  }
         }
    }

    Disable HTML tags in descriptions

    This code disables HTML tags in Description and Short Description fields by substituting the tags with non-executing versions.
    doit();
     
    function doit(){ 
     var desc = current.description.toString();
     var shdesc = current.short_description.toString();
     if(desc.indexOf('script>')>-1|| shdesc.indexOf('script>')>-1){
       desc = desc.replace(/<script>/g,"(script)");
       current.description = desc.replace(/<\/script>/g,"(\/script)");
       shdesc = shdesc.replace(/<script>/g,"(script)");
       current.short_description = shdesc.replace(/<\/script>/g,"(\/script)");}
    }

    Eliminate leading and trailing spaces in fields

    This example of the script trims trailing and leading spaces in the FirstName and LastName fields of the sys_user.
    doit();
     
    function doit(){ 
      var now_GR =new GlideRecord('sys_user');
      gr.query();
      while(gr.next()){
        if((gr.first_name.toString().length!= gr.first_name.toString().trim().length)||(gr.last_name.toString().length!= gr.last_name.toString().trim().length)){
         gr.first_name= gr.first_name.toString().trim();
         gr.last_name= gr.last_name.toString().trim();
         gr.autoSysFields(false);
         gr.update();}}
    }

    Make a field label flash

    The following client script example is for the number field on incident. The label flashes for two seconds.
    g_form.flash("incident.number","#FFFACD",0);
    The arguments for the flash method are as follows:
    • tablename.fieldname
    • RGB color or acceptable CSS color like "blue" or "tomato"
    • Integer that determines how long the label flashes:
      • 2 for a 1-second flash
      • 0 for a 2-second flash
      • -2 for a 3-second flash
      • -4 for a 4-second flash
    Note:
    Do not specify this argument if you want the field label colored the specified color.

    Make a field label bold

    This client script makes the label of a particular field bold. In this case, the field is the Short Description on the Incident Table.
    function onLoad(){
      var l = g_form.getLabel('incident.short_description');
      l.style.fontWeight = 'bold';}

    Make fields read-only

    This onLoad client script makes the following fields on the Incident [incident] table read-only:
    • Incident state
    • Impact
    • Urgency
    • Priority
    • Configuration item
    • Assigned to
    The script also removes the magnifying glass for the read-only Reference Fields (Configuration item and Assigned to).
    function onLoad(){
    var incidentState = g_form.getValue('incident_state');
    if( incidentState == '6'|| incidentState == '7'){
       g_form.setReadonly('incident_state',true);
       g_form.setReadonly('impact',true);
       g_form.setReadonly('urgency',true);
       g_form.setReadonly('priority',true);
       g_form.setReadonly('cmdb_ci',true);
       g_form.setReadonly('assigned_to',true);}}

    Set current date/time in field

    You can set date and time values in client scripts and script includes.

    Client script
    You can use the following two lines to set the current date and time in a date/time field. This approach bypasses the problem of getting the value into the proper format and proper time zone.
    var ajax = new GlideAjax('MyDateTimeAjax');
      ajax.addParam('sysparm_name','nowDateTime');
      ajax.getXML(function(){
        g_form.setValue('put your field name here', ajax.getAnswer());});
    For more information on running server-side scripts with the client, refer to GlideAjax.
    System script include
    // Be sure the Glide AJAX enabled option is checked
     
    var MyDateTimeAjax = Class.create();
    MyDateTimeAjax.prototype = Object.extendsObject(AbstractAjaxProcessor,{
      nowDateTime:function(){
        return gs.nowDateTime();}});

    Toggle the timer field by field name

    The following client script toggles the timer field based on a particular field name.
    function toggleTimerByFieldName(fieldName){
     //Step 1: Find the timer object
     //timeObjectName: the timer objects name as it would normally be referenced
     //timeObjectHidden: the hidden input node in the field td
     //timeObjectParent: the parent td node containing the field and it's constituent nodes
     //timeObjectFields: anchor tag with onclick to stop timer
     
     var timeObjectName = fieldName;
     var timeObjectHidden = gel(timeObjectName);
     
     //Step 2: simulate click stop button
     var timeObjectParent;
     var timeObjectFields;
     
     //verify that we got the correct object
     if(timeObjectHidden.type=="hidden"){
     
        //Get Parent td node
        timeObjectParent = timeObjectHidden.parentNode;
     
        //Get input fields
        timeObjectFields = timeObjectParent.getElementsByTagName("input");
     
        //simulate click of stop button
        var timerTestString ="paused";
        var timerImg;
     
        //loop through input objects looking for the pause timer object
        for(var elIt=0; elIt < timeObjectFields.length; elIt++){
          if(timeObjectFields[elIt].id.match(timerTestString)){
            if(timeObjectFields[elIt].value=="false"){
              timeObjectFields[elIt].value="true";
              timerImg = timeObjectParent.getElementsByTagName("img")[0];
              timerImg.src="images/timer_start.gifx";}
          elseif(timeObjectFields[elIt].value=="true"){
              timeObjectFields[elIt].value="false";
              timerImg = timeObjectParent.getElementsByTagName("img")[0];
              timerImg.src="images/timer_stop.gifx";}}}}}

    Modify GlideDateTime field values

    The following server-side script example shows how to modify values using the GlideDateTime API. The same concept also applies to the GlideDate object.
    Note:
    The following script is only intended for global applications.
    //You first need a GlideDateTime object
    //this can be from instantiating a new object "var gdt = new GlideDateTime()"
    //or getting the object from a GlideDateTime field
    //getting the field value (for example: var gdt = current.start_date) only returns the string value, not the object
    //to get the object use var gdt = current.start_date.getGlideObject(); (GlideElement)
    //now gdt is a GlideDateTime object
    var gdt = current.start_date.getGlideObject();
     
    //All methods can use negative values to subtract intervals
     
    //add 1 hour (60 mins * 60 secs)
    gdt.addSeconds(3600);
     
    //add 1 day
    gdt.addDaysLocalTime(1);
     
    //subtract 1 day
    gdt.addDaysLocalTime(-1);
     
    //add 3 weeks
    gdt.addWeeksLocalTime(3);
     
    //subtract 6 months
    gdt.addMonthsLocalTime(-6);
     
    //add 1 year, representing the date and time using the UTC timezone instead of the local user's timezone.
    gdt.addYearsUTC(1);
     
    //set the value of the GlideDateTime object to the current session timezone/format
    GlideSession.get().setTimeZoneName('US/Eastern');
    gdt.setDisplayValue('2018-2-28 00:00:00');
    gs.info('In ' + GlideSession.get().getTimeZoneName() + ": " + gdt.getDisplayValue());
    See also: