Stop users from submitting empty forms

Question

Stop users from submitting empty forms

I'm facing an issue with my form where I want to prevent it from being submitted if the fields are blank and also highlight those blank fields. The code I currently have works when trying to submit with blank fields, but for some reason, it doesn't submit when the fields are filled out. I can't seem to figure out what's wrong. Any help would be greatly appreciated.

Here is the JavaScript code I am using:

function CheckFields(){
    if((document.getElementById('title').value=="") || (document.getElementById("textfield").value=="")){
        const formElement = document.querySelector('form');
        formElement.addEventListener('submit',event =>{
            event.preventDefault();

            alert("Please fill out all fields before submitting");
            document.getElementById("title").style.backgroundColor=red;
            document.getElementById("title").style.backgroundColor=red;
        });
    }

And here is the relevant HTML code:

<input name="post" type="submit" value="Post" onclick="CheckFields();">

javascript html css forms

Answer 1

Answer №1

Copied from: https://developer.mozilla.org/en-US/docs/Learn/Forms/Form_validation in order to provide a consistent answer for this question, given that the webpage content may be updated periodically.

Utilizing pre-built form validation One of the key advantages of HTML5 form elements is the capability to validate user input without the need for JavaScript. This validation is achieved by using specific attributes on form fields. Some common validation attributes include:

required: Indicating whether a field must be completed before submitting the form. minlength and maxlength: Setting minimum and maximum lengths for text data.

min and max: Defining minimum and maximum values for numerical inputs.

type: Specifying the expected format of the data, such as a number, email address, or other predefined type.

pattern: Describing a regular expression pattern that the entered data must adhere to.

Answer 2

Copied from: https://developer.mozilla.org/en-US/docs/Learn/Forms/Form_validation in order to provide a consistent answer for this question, given that the webpage content may be updated periodically.

Utilizing pre-built form validation One of the key advantages of HTML5 form elements is the capability to validate user input without the need for JavaScript. This validation is achieved by using specific attributes on form fields. Some common validation attributes include:

required: Indicating whether a field must be completed before submitting the form. minlength and maxlength: Setting minimum and maximum lengths for text data.

min and max: Defining minimum and maximum values for numerical inputs.

type: Specifying the expected format of the data, such as a number, email address, or other predefined type.

pattern: Describing a regular expression pattern that the entered data must adhere to.

Answer 3

Answer №2

Typically, validating fields in this manner is not considered best practice. However, the issue in your code lies in the order of the condition and form submit event. Here is how it should be structured:

var myForm = document.querySelector('form');
var myTitle = document.getElementById('title');
var myTextfield = document.getElementById('textfield');
myForm.addEventListener('submit', event=>{
     if(myTitle.value=="" || myTextfield.value==""){
         alert("Please fill out all fields before submitting the form");
         myTitle.style.backgroundColor=red;
         myTextfield.style.backgroundColor=red;
         return false;
     } else {
         return true;
     };
});

Answer 4

Typically, validating fields in this manner is not considered best practice. However, the issue in your code lies in the order of the condition and form submit event. Here is how it should be structured:

var myForm = document.querySelector('form');
var myTitle = document.getElementById('title');
var myTextfield = document.getElementById('textfield');
myForm.addEventListener('submit', event=>{
     if(myTitle.value=="" || myTextfield.value==""){
         alert("Please fill out all fields before submitting the form");
         myTitle.style.backgroundColor=red;
         myTextfield.style.backgroundColor=red;
         return false;
     } else {
         return true;
     };
});

Answer 5

Answer №3

Enhance your input fields with the required attribute to enable client-side validation. For more robust validation, consider incorporating server-side validation through a model.

Observe the implementation of required:

            <form action="/action_page.php">
                <label for="fname">First name:</label><br>
                <input type="text" id="fname" name="fname" value="" required><br>
                <label for="lname">Last name:</label><br>
                <input type="text" id="lname" name="lname" value="Doe"><br><br>
                <input type="submit" value="Submit">
            </form>

Answer 6

Enhance your input fields with the required attribute to enable client-side validation. For more robust validation, consider incorporating server-side validation through a model.

Observe the implementation of required:

            <form action="/action_page.php">
                <label for="fname">First name:</label><br>
                <input type="text" id="fname" name="fname" value="" required><br>
                <label for="lname">Last name:</label><br>
                <input type="text" id="lname" name="lname" value="Doe"><br><br>
                <input type="submit" value="Submit">
            </form>

Answer 7

Answer №4

There are numerous methods to validate a form. With Html 5 forms, you have the option to include 'required' for client-side validation. Server-side validation is another approach that can be utilized. Real-time form validation using ajax is also a popular choice. Additionally, focusing on a field can help highlight areas that have not been filled out.

Answer 8

There are numerous methods to validate a form. With Html 5 forms, you have the option to include 'required' for client-side validation. Server-side validation is another approach that can be utilized. Real-time form validation using ajax is also a popular choice. Additionally, focusing on a field can help highlight areas that have not been filled out.

Stop users from submitting empty forms

Answer №1

Answer №2

Answer №3

Answer №4

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