gs.getProperty('glide.servlet.uri') catalog client script - How to get dynamic url of instance

[Edxavier Robert]

Hi, I have catalog client script where I need to get the dynamic URL of the current instance.  I was reading that I need to create a script include and use a GlideAjax to call it. But is returning null. So far this is what I got. 

Script Include

Client callable is set to true

var GetURL = Class.create();
GetURL.prototype = Object.extendsObject(AbstractAjaxProcessor, {

    getUrlDetails: function() {
        var instanceURL = gs.getProperty('glide.servlet.uri');
        
		return instanceURL;
    },

    type: 'GetURL'
});

 Catalog client script

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }
    
    //Type appropriate comment here, and begin script below
    var Sys = g_form.getValue('software_items');
    var instance = new GlideAjax('GetURL');
    instance.addParam('sysparam_name', 'url');
    instance.getXML(GetUrlPlease);
	
	function GetUrlPlease(response){
		var answer = response.responseXML.documentElement.getAttribute("answer");
		alert(answer);
	}
        if (newValue !== 'none') {
        var url = answer + 'sp?id=sc_cat_item&sys_id=' + Sys + '&sysparm_category=69d0e41b1b5f8150a190ece0f54bcb4e',
            _blank;
        top.window.open(url, "_blank");
    }
}

[Amit Dey]

hi @Edxavier Robert can we use variable name in this URL like url = answer + current.variables.variable_name + .......

like this ?