仅在完成函数A，B和C之后如何调用函数D

Question

Hi guys I'd like to know if its possible to call function "confirm" only IF functions checkV, checkV1, checkV2 are done and the form is completly filled in.

HTML & javascript

http://pastebin.com/xY1MBhv5

 function checkV() { var check = document.getElementById("voornaam").value; if (isNaN(check) || check.length == 0) { return true; } else { alert("In de naamvelden geen cijfers invoeren svp"); } }; function checkV1() { var check1 = document.getElementById("achternaam").value; if (isNaN(check1) || check1.length == 0) { return true; } else { alert("In de naamvelden geen cijfers invoeren svp"); } }; function checkV2() { var check2 = document.getElementById("toneelspeler").value; if (isNaN(check2) || check2.length == 0) { return true; } else { alert("In de naamvelden geen cijfers invoeren svp"); } }; function confirm() { var voorNaam = document.getElementById("voornaam").value; var toneelNaam = document.getElementById("toneelspeler").value; var achterNaam = document.getElementById("achternaam").value; alert("Beste " + voorNaam + " " + achterNaam + ", ontzettend bedankt voor je wens, we zullen ervoor zorgen dat " + toneelNaam + " je wens zal ontvangen!"); }; window.onload = function() { document.getElementById('submit').onclick = function() { checkV() checkV1() checkV2() confirm() }; }; 

 <header> <div id="logo"> <a href="home.html"> <img src="logo.png" id="home" alt="Logo van Het Imperium Theater"> </a> <a href="http://www.facebook.com" target="blank"> <img src="facebook.png" id="facebook" alt="facebook" /> </a> <a href="http://www.twitter.com" target="blank"> <img src="twitter.png" id="twitter" alt="twitter" /> </a> </div> <nav> <ul> <li><a href="Home.html">Home</a> </li> <li><a href="Agenda.html">Agenda</a> </li> <li><a href="Het Theater.html">Het Theater</a> </li> <li><a href="Ontdek Leiden.html">Ontdek Leiden</a> </li> <li><a href="Contact.html">Contact</a> </li> </ul> </nav> </header> <div id="wrapper"> <form id="form" name="form"> <h1>Verstuur een wens.</h1> <div id="forms"> <label for="voornaam">Voornaam: <input type="text" name="name" id="voornaam" placeholder="uw voornaam" name="fname" required> </label> <label for="achternaam">Achternaam: <input type="text" name="name" id="achternaam" placeholder="uw achternaam" name="fname" required> </label> <label for="toneelspeler">Naam toneelspeler: <input type="text" name="name" id="toneelspeler" placeholder="naam van de toneelspeler" name="fname" required> </label> <label for="boodschap">Uw wens: <textarea rows="4" cols="20" name="name" placeholder="Type hier uw wens" required></textarea> </label> </div> <input type="submit" value="Submit" id="submit"> </form> </div> <footer> <a href="home.html"> <p>Theater Imperium</p> </a> <p>Oude Vest 33e</p> <p>2312 XR Leiden</p> <p>071 5141035</p> <p>&copy; Arpiar Melikjan</p> </footer> 

Answer 1

According to the link provided, if everything goes fine, checkV(), checkV1() and checkV2() will return true , otherwise undefined . You can do something like this:

if(checkV() && checkV1() && checkV2())
    //Do submit

EDIT:

If you want more control over your control flow (which might be helpful in debugging), you might do something like this:

if(checkV()) {
    if(checkV1()) {
        if(checkV2()) {
            //Do submit
        }
    }
}

Now, you can associate else blocks, and can take action according to the method which failed to validate your input.