How to edit the function of "Attach" button on related search record in incident

[VIKAS MISHRA]

Whenever i click on attach button it general the KB article url/link and add that to additional comment, but i want that when we click on attach button it should actually fetch that KB article no. from the additonal comment and add it to the new reference field "Knowledge article" that i just have created.

I do not want to amend the OOB script include "cxs_Knowledge".

Can we create a on change client script of BR through which i can acive this. 

Below is the Client script i got where there are editing that URL getting pasted in additional comment, so can we edit this script of acive what i want.

function onChange(control, oldValue, newValue, isLoading, isTemplate) {
	if (isLoading || newValue === '') {
		return;
  }

  if(newValue.includes('kb_view')){

		// gets form value from Additional comments fields
		var comment = g_form.getValue('comments');

		// retrieve KB link between [code] blocks
		var commentLink = comment.substring(
			comment.lastIndexOf('[code]') + 6,
			comment.lastIndexOf('[/code]')
		);

		// retrieve KB number from URL
		var kbNumberSub = commentLink.match(' >(.*) : ')[1];
		var kbNumber = trim(kbNumberSub);

		// query to retrieve KB article data
		var gr = new GlideRecord('kb_knowledge');
		gr.addQuery('number', kbNumber);
		gr.orderByDesc('sys_created_on');
		gr.setLimit(1);
		gr.query();
		gr.next();

		// KB Number
		var KBNum = gr.getValue('number');
		// KB Title
		var KBTitle = gr.getValue('short_description');
		// KB Knowledge Base
		var KBKnowledgeBase = gr.getValue('kb_knowledge_base');

		// query to retrieve portal data
		var url = new GlideRecord('sp_portal');
		url.addQuery('kb_knowledge_base', KBKnowledgeBase);
		url.orderByDesc('sys_created_on');
		url.setLimit(1);
		url.query();
		url.next();

		// portal URL suffix
		var portal = url.getValue('url_suffix');

		// replace Additional comments fields with new URL
		g_form.setValue("comments", newValue.replace(comment, "[code]<a title='"+KBNum+": "+KBTitle+"' href='"+portal+"?id=kb_article&sysparm_article="+KBNum+"'>"+KBNum+": "+KBTitle+"</a>[/code]"));

  }
}