jstest.maxpat

{
	"patcher" : 	{
		"fileversion" : 1,
		"appversion" : 		{
			"major" : 6,
			"minor" : 1,
			"revision" : 0,
			"architecture" : "x86"
		}
,
		"rect" : [ 54.0, 94.0, 117.0, 172.0 ],
		"bglocked" : 0,
		"openinpresentation" : 0,
		"default_fontsize" : 12.0,
		"default_fontface" : 0,
		"default_fontname" : "Arial",
		"gridonopen" : 0,
		"gridsize" : [ 15.0, 15.0 ],
		"gridsnaponopen" : 0,
		"statusbarvisible" : 2,
		"toolbarvisible" : 1,
		"boxanimatetime" : 200,
		"imprint" : 0,
		"enablehscroll" : 1,
		"enablevscroll" : 1,
		"devicewidth" : 0.0,
		"description" : "",
		"digest" : "",
		"tags" : "",
		"boxes" : [ 			{
				"box" : 				{
					"fontname" : "Arial",
					"fontsize" : 12.0,
					"id" : "obj-79",
					"maxclass" : "flonum",
					"numinlets" : 1,
					"numoutlets" : 2,
					"outlettype" : [ "float", "bang" ],
					"parameter_enable" : 0,
					"patching_rect" : [ 15.0, 15.0, 50.0, 20.0 ]
				}

			}
, 			{
				"box" : 				{
					"fontname" : "Arial",
					"fontsize" : 12.0,
					"id" : "obj-77",
					"maxclass" : "flonum",
					"numinlets" : 1,
					"numoutlets" : 2,
					"outlettype" : [ "float", "bang" ],
					"parameter_enable" : 0,
					"patching_rect" : [ 15.0, 99.919983, 50.0, 20.0 ]
				}

			}
, 			{
				"box" : 				{
					"fontname" : "Arial",
					"fontsize" : 12.0,
					"id" : "obj-75",
					"maxclass" : "newobj",
					"numinlets" : 1,
					"numoutlets" : 1,
					"outlettype" : [ "" ],
					"patching_rect" : [ 15.0, 65.248047, 78.0, 20.0 ],
					"saved_object_attributes" : 					{
						"filename" : "lowpass.js",
						"parameter_enable" : 0
					}
,
					"text" : "js lowpass.js"
				}

			}
 ],
		"lines" : [ 			{
				"patchline" : 				{
					"destination" : [ "obj-77", 0 ],
					"disabled" : 0,
					"hidden" : 0,
					"source" : [ "obj-75", 0 ]
				}

			}
, 			{
				"patchline" : 				{
					"destination" : [ "obj-75", 0 ],
					"disabled" : 0,
					"hidden" : 0,
					"source" : [ "obj-79", 0 ]
				}

			}
 ],
		"dependency_cache" : [  ]
	}

}

lowpass.js

inlets = 2;
outlets = 1;

var amount = 0.3;
var filterd = 0.0;

function msg_float(a)
{
	if (inlet == 0)
	{
		filterd = (a* amount) + (filterd * (1 - amount));
		outlet(0, filterd);
	}
	
	if (inlet == 1)
	{
		amount = a;
		post(amount);
		return;
	}
};