var get_param_vars;
var get_param_vals;

function get_param(nm)
{
    if (!get_param_vars) {
	var get_param_query = window.location.search.substring(1);
	var params = get_param_query.split("&");
	get_param_vars = [];
	get_param_vals = [];
	for (var i = 0; i < params.length; i++) {
	    var pair = params[i].split("=");
	    get_param_vars[i] = pair[0];
	    get_param_vals[i] = pair[1];
	}
    }

    for (var i = 0; i < get_param_vars.length; i++) {
	if (get_param_vars[i] == nm) {
	    return get_param_vals[i];
	}
    }

    return null;
}