How to make form only submit if all functions retu

问题:

I want my form to only submit if all my JavaScript functions return true.

Here is my Javascript code:

function validateUserName(NewUser)
{
    var u = document.forms["NewUser"]["user"].value
    var uLength = u.length;
    var illegalChars = /\W/; // allow letters, numbers, and underscores
    if (u == null || u == "")
    {
        alert("You left Username field empty");
        return false;
    }
    else if (uLength <4 || uLength > 11)
    {
        alert("The Username must be between 4 and 11 characters");
        return false;
    }
    else if (illegalChars.test(u)) 
    {
        alert("The username contains illegal characters");
        return false;
    }
    else
    {
        return true;
    }
}


function validatePassword(NewUser)
{
    var p = document.forms["NewUser"]["pwd"].value
    var cP = document.forms["NewUser"]["confirmPwd"].value
    var pLength = p.length;
    if (p == null || p == "")
    {
        alert("You left the password field empty");
        return false;
    }
    else if (pLength < 6 || pLength > 20)
    {
        alert("Your password must be between 6 and 20 characters in length");
        return false;
    }
    else if (p != cP)
    {
        alert("The passwords do not match!");
        return false;
    }
    else
    {
        return true;
    }
}

function validateEmail(NewUser)
{
    var e = document.forms["NewUser"]["email"].value
    var eLength = e.length;
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
    var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;

    if (eLength == "" || eLength == null) 
    {

        alert("You left the email field blank!");
        return false;
    } 
    else if (e.match(illegalChars)) 
    {

        alert("ILEGAL CHARECTORS DETECTED EXTERMINATE");
        return false;
    } 
    else 
    {
        return true;
    }
}
function validateFirstName(NewUser)
{
    var f = document.forms["NewUser"]["fName"].value;
    var fLength = f.length;
    var illegalChars = /\W/;

    if(fLength > 20)
    {
        alert("First Name has a max of 20 characters");
        return false;
    }
    else if (illegalChars.test(f))
    {
        alert("Numbers,letter and underscores in first name only");
        return false;
    }
    else 
    {
        return true;
    }


}

function validateLastName(NewUser)
{
    var l = document.forms["NewUser"]["lName"].value;
    var lLength = l.length;
    var illegalChars = /\W/;

    if(lLength > 100)
    {
        alert("Last Name has a max of 100 characters");
        return false;
    }
    else if (illegalChars.test(f))
    {
        alert("Numbers,letter and underscores in last name only");
        return false;
    }
    else 
    {
        return true;
    }


}

function validateForm()
{
    //call username function
    validateUserName();

    //call password function
    validatePassword();

    //call email function
    validateEmail();

    //call first name function
    validateFirstName();

    //call first name function
    validateLastName();
}

Here is my HTML:

<table id = "SignUpTable">
        <p id = "SubHeading">Sign Up.</p>
            <form name = "NewUser" onsubmit= "validateForm()" action = "">
                <tr>
                <td class = "FieldName">Username:</td> 
                <td class = "TextField"><input type = "text" name = "user"/></td> 
                </tr>
                <tr>
                <td class = "Information"><em>Must be 4-11 characters.<br/>Only numbers, letters and underscores.</em></td>
                </tr>

                <tr>
                <td class = "FieldName">Email:</td> 
                <td class = "TextField"><Input type = "text" name = "email"/></td>
                <tr>
                <td  class = "Information"><em>We need this to verify your account.</em></td>
                </tr>

                <tr>
                <td class = "FieldName">Password:</td>
                <td class = "TextField"><input type = "password" name = "pwd"/></td>
                <tr>
                <td  class = "Information"><em>6-20 characters</em></td>
                </tr>

                <tr>
                <td class = "FieldName">Confirm Password:</td>
                <td class = "TextField"><input type = "password" name = "confirmPwd"/></td>
                <tr>
                <td  class = "Information"><em>just in case you didn't make mistakes!</em></td>
                </tr>

                <!-- Optional -->


                <tr>
                <td class = "FieldName">First Name:</td>
                <td class = "TextField"><input type = "text" name = "fName"/></td>
                <tr>
                <td  class = "Information"><em>optional</em></td>
                </tr>

                <tr>
                <td class = "FieldName">Lastname:</td>
                <td class = "TextField"><input type = "text" name = "lName"/></td>
                <tr>
                <td  class = "Information"><em>(optional)</em></td>
                </tr>

                <tr>
                <td><input type = "submit" value = "Submit"/></td>
                </tr>

        </table>



            </form>
    </div>

And here is a JS Fiddle:

http://jsfiddle.net/vK9aJ/

(Please ignore the bad sizing in the form)

回答1:

function validateForm() {
    if(validateUserName() && validatePassword() && validateEmail() && validateFirstName() && validateLastName()) return true;
    else return false;
}

Depending on the return of your function you can chose to submit the form or not.

回答2:

You can also optimize the previous answers this way:

If one of your functions returns false, then the expression will be set to false.

function validateForm() {
    return validateUserName()
        && validatePassword()
        && validateEmail()
        && validateFirstName()
        && validateLastName()
    ;
}

回答3:

Use this:

function validateForm() {
    if (
           validateUserName()
        && validatePassword()
        && validateEmail()
        && validateFirstName()
        && validateLastName()
    ) {
        return true;
    }

    return false;
}

回答4:

Call a single function, for example validate() and from it call the other functions which you have used. If all the functions return true, only then the function validate() returns true.

    function validate() 
    { 
      if(validateUserName() && validatePassword() && validateEmail() && validateFirstName() && validateLastName())
       return true;
      else 
       return false;
    }