Show data on a form from another table

[Jamie Sherry]

I'm trying to pull related data from one table onto the form for another table. I've been reading over previous similar posts but still having trouble. I'm new to scripting so I can't quite interpret what I'm reading to adapt it to my needs. Here's what I'm trying to achieve:

Whenever I create a new hardware model entry into the system, it is assigned a category. On the equipment form, I want to show display that category when the model is selected. 

I would really appreciate if someone would break it down for me with some context explanation. 

[Nandini Sahay1]

Hi @Jamie Sherry , 

Please write a client script and a script include to achieve this. 
The client-side script passes parameters to the Script Include. The Script Include returns data as XML or a JSON object.

Glide Ajax - The GlideAjax class is used by client-side scripts to send data to and receive data from the ServiceNow server. 
Please go through the below link for more information on how it works- 

https://developer.servicenow.com/dev.do#!/learn/learning-plans/quebec/new_to_servicenow/app_store_le...

Script - 
Note - Kindly place the script name , backend value name , function name etc. 

On change / On load client script - 

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }
var xy = g_form.getValue(‘backend name of field’);
    var ga = new GlideAjax(‘Scriptt include name’ );
    ga.addParam('sysparm_name, ‘function name’); // function name which is defined in script include 
ga.addParam('sysparm_backend value of filed’, xy); //  value which is stored in variable - xy 
ga.getXML(callback);
    
    function callback(response){
        
        var answer = response.responseXML.documentElement.getAttribute("answer");
        
        g_form.setValue(‘backend value of field’,answer);


Script Include -

var Script Include Name  = Class.create();
Script Include name.prototype = Object.extendsObject(AbstractAjaxProcessor, {

	function name: function(){
		
		var am = this.getParameter('sysparm_backend field name’ );// same backend field name which is mentioned in 
		var getData =new GlideRecord(‘table name’);
		getData.addQuery(‘’);  //if you want to query any other things from table
                getData.query();            
	if(getData.next()){
			
			return getData.getValue(‘backend field name’); // value which u want to fetch from table  

		}
},
	
    type: ‘Script Include name’
});

Please mark correct , if it solves your query . 

Thank You !
Regards, 

Nandini