[RESOLVED] Calling functions from functions

[chris1990]

Is there a way to call another function (e.g function2) from a function (e.g function1), but have the rest of the code in (function1) wait to be executed until the (function2) is finished being executed.

Thanks in advance,

Chris1990

[SambaNeko]

Javascript is synchronous; unless you're doing something with AJAX, timers, or callbacks, then this is the normal state of the language.

[chris1990]

Thanks for your reply, below is my javascript code,

In order to calculate the fare you need to know the distance first. So when you call the 'calcFare' function, it first calls the 'calcRoute' function, which calculates and stores the distance in a hidden input field ('txtDistance'), then the 'calcFare' function reads this and calculates the fare.

I currently have a button for both functions, but i am trying to delete the 'calcRoute' button, and instead call it from the 'calcFare' function. When i use the 'calcFare' button it doesn't seem to call the 'calcRoute' function, and only works if i press the 'calcFare' button twice or press the 'calcRoute' button first.

i think its because its awaiting feedback from the google maps api, and it is executing the rest of the code before getting the feedback.

<script type="text/javascript">
  var directionDisplay;
  var directionsService = new google.maps.DirectionsService();
  var Gdistance;
  var map;

  function initialize() {
    directionsDisplay = new google.maps.DirectionsRenderer();
    var Office = new google.maps.LatLng(53.593338, -2.222371);//41.850033:-87.6500523
    var myOptions = {
      zoom:13,
      mapTypeId: google.maps.MapTypeId.ROADMAP,
      center: Office
    }
    map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
    directionsDisplay.setMap(map);
  }
  
  function calcRoute() {
    var start = document.getElementById("start").value;
    var end = document.getElementById("end").value;
    var request = {
        origin:start, 
        destination:end,
        travelMode: google.maps.DirectionsTravelMode.DRIVING
    };
    directionsService.route(request, function(response, status) {
    //  if (status == google.maps.DirectionsStatus.OK) {
        directionsDisplay.setDirections(response);
		Gdistance = response.routes[0].legs[0].distance.value;
		Gdistance = Gdistance * 0.000621371192;
		var roundedNumber = roundNumber(Gdistance,2);
		document.getElementById('txtDistance').value = roundedNumber;
      	    });
  }
// Round Up Number to 1/2 Descimals
  function roundNumber(num, dec) {
	var result = Math.round(num*Math.pow(10,dec))/Math.pow(10,dec);
	return result;
	}

// Calculate Fare
  function calcFare() {
  //calculate route first
  calcRoute()
  // variables
	var fareResult
	var firstMile = 2.20;
	var pricepMile = 1.80;
	var distance = document.getElementById('txtDistance').value;

  // calculator for Car
  		//exc 1st mile and calc rest of miles by PPM
  			fareResult = (distance - 1) * pricepMile
  		//inc first mile
  			fareResult = fareResult + firstMile		
  // show fare result
	var roundedNumber = roundNumber(fareResult,2);
		if (roundedNumber < 1.675) {roundedNumber = "1.70"};	
	document.getElementById('txtFare').value = roundedNumber;
	calcType();
	}
	
	function calcType() {
    var VehType = document.getElementById("sVehicle").value;
	var EstFare = document.getElementById("txtFare").value;
	var FinalFare = ""
	
    	if (VehType == "car")
    		{FinalFare = EstFare}
    	if (VehType == "estate")
    	   	{FinalFare = EstFare * 1.25 };
    	if (VehType == "bus")
       		{FinalFare = EstFare * 1.50};
    	if (VehType == "exec")
	       	{FinalFare = EstFare * 1.75};
	       	
	var roundedNumber = roundNumber(FinalFare,2); 
    document.getElementById("txtTypeFare").value = roundedNumber
	}
			
</script>

[SambaNeko]

When an AJAX request (which is being made in your calcRoute() function) is made, you set up a callback to be executed when you receive a response. So the callback is a good place to put any functionality that should only execute after the (successful) request.

So, call your calcRoute() function from a button, and then call calcFare() from the callback in calcRoute(). This is a simplified example:

  function calcRoute() {
    var start = document.getElementById("start").value;
    var end = document.getElementById("end").value;
    var request = {
        origin:start, 
        destination:end,
        travelMode: google.maps.DirectionsTravelMode.DRIVING
    };
    directionsService.route(request, function(response, status) {
    //  if (status == google.maps.DirectionsStatus.OK) {
        directionsDisplay.setDirections(response);
		Gdistance = response.routes[0].legs[0].distance.value;
		Gdistance = Gdistance * 0.000621371192;
		var roundedNumber = roundNumber(Gdistance,2);
		document.getElementById('txtDistance').value = roundedNumber;
               calcFare();
      	    });
  }

...

// Calculate Fare
  function calcFare() {
  //calculate route first
  //calcRoute()

...

[chris1990]

thanks,

Chris1990