JavaScript from an old project. Using Foursquare, Leaflet, and Twilio APIs.

main.js

var _map;
var _group;
var _userLocation;

$(document).ready(function(){

	var url = location.pathname.substring(location.pathname.lastIndexOf('/')+1);
	if (url == 'map') {
		LoadMapPage();
	}

});

function LoadMapPage(){
	InitLocation();
}

function searchfoursquare(){

	_group.clearLayers();

	var query = $('#maptext').val();

	var url = 'https://api.foursquare.com/v2/venues/search?';
	url += 'll=' + _userLocation[0] + ',' + _userLocation[1];
	url += '&radius=10000';
	url += '&intent=browse';
	url += '&query=' + query;
	url += '&client_id=5H3DCCHXFK2FXO5EVDA4RH4APOOKAOR5IP4JLDG4VAZNIDOM';
	url += '&client_secret=GB1VDJYA0TB2QTPBK4RWIV0LTRSW1N5KIKFX2ZSYWEZY2ZAG';
	url += '&v=20130815';

	$.getJSON(url, {}, function (data) {
	// notice that the data can be accessed like a multi-dimensional array
	list = data['response']['venues'];
	for (var i = 0; i < list.length; i++) {
		var venue = list[i];

		// create the icon for the map
		var id = venue['id'];
		var lat = venue['location']['lat'];
		var lng = venue['location']['lng'];

		if (venue['categories'].length === 0)
			continue;

		var category = venue['categories'][0];
		var path = category['icon'].prefix + "32" + category['icon'].suffix;
		var newIcon = CreateIcon(path, '');

		var marker = AddMapMarker(id, lat, lng, path, newIcon);

		// create a popup with some basic info about the venue
		var name = venue['name'];
		var html = '<h2>' + name + '</h2>';

		if (typeof venue['contact']['phone'] != "undefined") {
			html += '<div class="item"><a href="tel:' + venue['contact']['phone'] + '">' + venue['contact']['formattedPhone'] + '</a></div>';
		}

		html += '<div class="item">Type: ' + category['shortName'] + '</div>';

		if (typeof venue['menu'] != "undefined") {
			var menuLink = venue['menu'].url;
			html += '<div class="item"><a href="' + menuLink + '">View Menu</a></div>';
		}

		html += SetupTwilioText(id, name, menuLink);  //added menuLink*************************

		marker.bindPopup(html);

		_group.addLayer(marker);

	}

	SetupTwilioEvents();
	});
}

function SendText(txt, name, menuLink){
	$.ajax({
		url: '/main/sendtext',
		type: 'POST',
		data: { text: txt, name: name, menuLink: menuLink }
	}).done(function(data){
		if (data === null)
			alert('Please try again.');
		else {
			$('.txtTextMessage').val('');
			$('.leaflet-popup').css('opacity', 0);
		}
	});
}

function SetupTwilioEvents(){
	$('body').on('keypress', '.txtTextMessage', function(e){
		if (e.keyCode == 13) {
			var txt = $(this).val();
			var name = $(this).parent().find('.hdnName').val();
			var menuLink = $(this).parent().find('.hdnMenu').val();
			SendText(txt, name, menuLink);
		}
	});

	$('body').on('click', '.btnSendText', function(){
		var txt = $(this).parent().find('.txtTextMessage').val();
		var name = $(this).parent().find('.hdnName').val();
		var menuLink = $(this).parent().find('.hdnMenu').val();
		SendText(txt, name, menuLink);
	});
}

function SetupTwilioText(id, name, menuLink){
	var html = '<input type="hidden" class="hdnID" value="' + id + '" />';
	html += '<input type="hidden" class="hdnName" value="' + name + '" />';
	html += '<input type="hidden" class="hdnMenu" value="' + menuLink + '" />';
	html += '<input type="text" class="txtTextMessage" placeholder="Text your friend!" />';
	html += '<button class="btnSendText">Send</button>';

	return html;
}

function InitLocation(){
	_map = L.map('map');
	_group = new L.LayerGroup();
	_map.addLayer(_group);

	L.tileLayer('http://{s}.tiles.mapbox.com/v3/dacur.i9gb8ifk/{z}/{x}/{y}.png', {
    attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>, Imagery © <a href="http://mapbox.com">Mapbox</a>',
    maxZoom: 18
	}).addTo(_map);

	var gl = navigator.geolocation;

	gl.getCurrentPosition(geoSuccess, geoError);

	$('#maptext').keypress(function(e){
		if (e.keyCode == 13){
			searchfoursquare();
		}
	});

}

function geoSuccess(position) {
	var latitude = position.coords.latitude;
	var longitude = position.coords.longitude;

	_userLocation = [latitude, longitude];
	_map.setView(_userLocation, 16);

	// AddMapMarker(null, latitude, longitude, null, icon)

	L.marker(_userLocation).addTo(_map); //changed from .addTo(_group)

}

function geoError(err) {
	if (err.code===0)
		alert('Sorry, something went wrong while getting your location');
	else if (err.code===1)
		alert('Mapper can\'t work if you don\'t allow us to locate you.');
	else if (err.code===2)
		alert('Sorry, we are having issues locating you.<br/>Please refresh and try again.')
	else if (err.code===3)
		alert('Sorry, we timed out looking for your location');
}

//*******NEW CODE BELOW*******

function AddMapMarker(id, lat, lng, path, icon) {
var latLng = new L.LatLng(lat, lng);
var marker = new L.Marker(latLng, { icon: icon });

_group.addLayer(marker);

return marker;
}

function CreateIcon(iconPath, className) {
	var icon = L.icon({
		iconUrl: iconPath,
		shadowUrl: null,
		iconSize: new L.Point(44, 55),
		//iconAnchor: new L.Point(16, 41),
		popupAnchor: new L.Point(0, -31),
		className: className
	});

	return icon;
}