Javascript Validation doesn't work

Question

I am new to javascript and I am attempting to create a simple form validation. When I hit the submit button nothing happens. I have been looking at examples for a while and I cannot seem to figure out where I am going wrong. Any suggestions:

HTML:

        <form name="myForm" class="appnitro" onsubmit="return validateForm()" action="mysql_connection.php" method="post">
            <div class="form_description">
                 <h2>Patient Record</h2>

                <p></p>
            </div>
            <ul>
                <li id="li_1">
                    <label class="description" for="element_1">&nbspName</label> 

        <span>
                <td width="68%"><input size="15" maxlength="30" class="input" type="text" name="Fname" id="Fname"></td>
                <label>First</label>
        </span>


        <span>
                <td width="68%"><input size="15" maxlength="30" class="input" type="text" name="Lname" id="Lname"></td>
                <label>Last</label>
        </span>

                    <li class="buttons">
                        <label class="description" for="element_1">&nbspGender</label> 

        <span>
                        <tr>
                    <select name="Gender"> 
                        </tr>
        </span>

                        <option value="Select">Select</option>
                        <option value="Male">Male</option>
                        <option value="Female">Female</option>
                        </select>
                        <li class="buttons">
                            <label class="description" for="element_3">&nbspAge</label> 

        <span>
                        <tr>
                    <select name="Age"> 
                        </tr>
        </span>

                            <script type="text/javascript">
                                listAge()
                            </script>
                            </select>
                            <li class="buttons">
                                <label class="description" for="element_3">&nbspPhone Number</label> 
        <span>
                 <td width="68%"><input size="25" maxlength="50" class="input" type="text" name="Phone" id="Phone"></td>
        </span>

                                <li class="buttons">
                                    <label class="description" for="element_3">&nbspEmail ID</label> 

        <span>
                <td width="68%"><input size="25" maxlength="50" class="input" type="text" name="Email" id="Email"></td>
        </span>

                                    <li class="buttons">
                                        <label class="description" for="element_3">&nbspAddress</label> 

        <span>
        <td><textarea cols="25" rows="3" class="input" name="Address" id="Address"></textarea></td>
        </span>

                                        <li class="buttons">
                                            <label class="description" for="element_3">&nbspReason For Visit</label> 

        <span>
        <td><textarea cols="25" rows="3" class="input" name="Reason" id="Reason"></textarea></td>
        </span>

                                            <li class="buttons">
                                                <label class="description" for="element_3">&nbspAttending Doctor</label> 

        <span>
        <td width="68%"><input size="25" maxlength="50" class="input" type="text" name="Doctor" id="Doctor"></td>
        </span>

                                                <li class="buttons">
                                                    <input type="submit" value="Submit" />
                                                    <input type="reset" value="Reset">
                                                </li>
            </ul>
        </form>

Javascript:

    <script>
        function validateForm() {
            var Fname = document.forms["myForm"]["Fname"].value;
            var Lname = document.forms["myForm"]["Lname"].value;
            var Phone = document.forms["myForm"]["Phone"].value;
            var Address = document.forms["myForm"]["Address"].value;
            var Reason = document.forms["myForm"]["Reason"].value;
            var Doctor = document.forms["myForm"]["Doctor"].value;

            var email = document.forms["myForm"]["email"].value;
            var atpos = email.indexOf("@");
            var dotpos = email.lastIndexOf(".");

            if (Fname == null || Fname == "") {
                alert("First name must be filled out");
                return false;
            }
            if (Lname == null || Lname == "") {
                alert("Last name must be filled out");
                return false;
            }
            if (Phone == null || Phone == "") {
                alert("Phone Number must be filled out");
                return false;
            }
            if (Address == null || Address == "") {
                alert("Address must be filled out");
                return false;
            }
            if (Reason == null || Reason == "") {
                alert("Reason for Visit must be filled out");
                return false;
            }
            if (Doctor == null || Doctor == "") {
                alert("Attending Doctor must be filled out");
                return false;
            }
            if (atpos < 1 || dotpos < atpos + 2 || dotpos + 2 >= x.length) {
                alert("Not a valid e-mail address");
                return false;
            }

        }

        function listAge() {
            var i = 1;

            for (i = 1; i <= 100; i++) {
                document.write("<option value=" + i + ">" + i + "</option>");
            }
        }
    </script>

Answer 1

Add this JavaScript code and it should word

    function validateForm() {
        var Fname = document.forms["myForm"]["Fname"].value;
        var Lname = document.forms["myForm"]["Lname"].value;





        if (Fname == null || Fname == "") {
            alert("First name must be filled out");
            return false;
        }
        if (Lname == null || Lname == "") {
            alert("Last name must be filled out");
            return false;
        }
        if (Phone == null || Phone == "") {
            alert("Phone Number must be filled out");
            return false;
        }
        if (Address == null || Address == "") {
            alert("Address must be filled out");
            return false;
        }
        if (Reason == null || Reason == "") {
            alert("Reason for Visit must be filled out");
            return false;
        }
        if (Doctor == null || Doctor == "") {
            alert("Attending Doctor must be filled out");
            return false;
        }
        if (atpos < 1 || dotpos < atpos + 2 || dotpos + 2 >= x.length) {
            alert("Not a valid e-mail address");
            return false;
        }

    }

    function listAge() {
        var i = 1;

        for (i = 1; i <= 100; i++) {
            document.write("<option value=" + i + ">" + i + "</option>");
        }
    }

I believe the problem is that you try to take some values from fields that not exists at least from the code that you provided! Just copy the code above and it should work for sure!

Answer 2

Why not directly use the ID attribute of the element as if you put an ID inside any element it is always preferred to keep it unique. So you can use document.getElementById("ID").value; to get the value of an individual element. Like this :

var firstName = document.getElementById("firstNameTextBox").value;

if(firstName == ''){       
    message.innerHTML = "First Name is required";
}

I have a demo that you should try.

Demo

Answer 3

@Quentin is right, you need to clean your HTML code and javascript code.

But you have an error in your Javascript. You need to write a capital E for the Email field. It is case sensitive.

Try with this :

var email = document.forms["myForm"]["Email"].value;

Answer 4

Your HTML is hideously invalid. Odds are that the browser is trying to perform error recovery and doing things like moving the <form> element outside the table (assuming there is a table, it doesn't show up in your code but you have table data cells in it) so that the submit button is no longer inside it and does not try to submit the form. (This is a known problem with trying to interleave forms a table rows).

Use a validator to find your errors then fix them.