Remove value from a list variable from the backend table

[Hari1]

Hi,

I have a requirement to remove the list variable value and I have a reference field value. If both the values are same then remove the matching value of the reference field from the list variable value. I need to achieve this using the OnChange - client script. Using the below script i am not able to clear the value of the list variable.

Client Script:

var arr;
var selectedOptions = g_form.getValue("u_am_val").split(',');
	
var ga = new GlideAjax('AmvalCheck); 
ga.addParam('sysparm_name', 'checkAM');
ga.addParam('sysparm_amVal', g_form.getValue("u_am_val"));
ga.addParam('sysparm_am', g_form.getValue("u_am"));
ga.getXML(updateCD);
	
function updateCD(response) {
var answer = response.responseXML.documentElement.getAttribute("answer");
		
arr = answer.split(",");
		
alert("arr.length: " + arr.length +",arr: " + arr.toString());
		
for (var i = 0; i < selectedOptions.length; i++) {
if (arr.indexOf(selectedOptions[i]) != -1) {
g_form.removeOption("u_am_val",selectedOptions[i]);
}
}
}

Script Include:

var amVal = this.getParameter('sysparm_amVal').toString().split(",");
		var am = this.getParameter('sysparm_am').toString();
		
		var arr = [];
		
        for (var i = 0; i < amVal.length; i++) {
            if (amVal [i] == am) {
                arr.push(amVal [i]);
            }
        }
		return arr.toString();

Thanks