HTML DOM forms Collection

Last Updated : 13 Jun, 2023

The DOM forms collection is used to return the collection of all <form> elements in a HTML document. The form elements are sorted as they appear in the source code.

Syntax:

document.forms

Properties: It returns the number of form in the collection of elements.

Methods: The DOM forms collection contains three methods which are listed below:

[index]: It is used to return the <form> element of the specified index. The index value starts at 0. NULL is returned if the index value is out of range.
item(index): It is used to return the <form> element of specified index. The index value starts at 0. NULL is returned if the index value is out of range. This method performs similarly to the above method.
namedItem(id): It is used to return the <form> element from the collection which matches the specified id. NULL is returned if the id does not exist.

Below programs illustrate the use of the documents.forms property in HTML:

Example 1: This example use length property to count number of form elements in the collection.

html

<!DOCTYPE html>
<html>
    <head>
        <title>
        HTML | DOM forms Collection
        </title>
    </head>
    
    <body>
        <h1 style = "color:green">GeeksForGeeks</h1>
        <h2>DOM document.forms Property</h2>
    
        <!-- form 1 starts from here -->
        <form id="personal-info">
            <h3>Personal Information Area</h3>
            Name: <input type="text">
        </form>
        <!-- form 1 ends here -->
        
        <!-- form 2 starts from here -->
        <form id="home-info">
            <h3>Home Address Information Area</h3>
            Address: <input type="text">
        </form>
        <!-- form 2 ends here -->
        
        <!-- form 3 starts from here -->
        <form id="delivery-info">
            <h3>Delivery Type Area</h3>
            Delivery Speed: <input type="text">
        </form>
        <!-- form 3 ends here -->
    
        <p>
         Click the button below to count 
         the number of forms:
        </p>
        
        <button onclick = "countForms()">
         Count forms
        </button>
    
        <p>
         The total number of forms in
         this page is: 
        </p>
        
        <div class = "count"></div>
        
        <script>
            function countForms() {
    
                // Count number of forms
                let collection = document.forms.length;
                document.querySelector(".count").innerHTML
                                          = collection;
            } 
        </script>
    </body>
</html>

Output:

Before Click on the button:

Count forms - before

After Click on the button:

Count forms - after

Example 2:

html

<!DOCTYPE html>
<html>
    <head>
        <title>
           HTML | DOM forms Collection
        </title>
    </head>
    
    <body>
        <h1 style="color:green">GeeksForGeeks</h1>
        <h2>DOM document.forms Property</h2>
    
        <!-- form 1 starts from here -->
        <form id = "personal-info">
            <h3>Personal Information Area</h3>
            Name: <input type="text">
        </form>
        <!-- form 1 ends here -->
        
        <!-- form 2 starts from here -->
        <form id="home-info">
            <h3>Home Address Information Area</h3>
            Address: <input type="text">
        </form>
        <!-- form 2 ends here -->
        
        <!-- form 3 starts from here -->
        <form id="delivery-info">
            <h3>Delivery Type Area</h3>
            Delivery Speed: <input type="text">
        </form>
        <!-- form 3 ends here -->
    
        <p>
         Click the button below to find 
         all form IDs:
        </p>
        <button onclick="findFormIDs()">
         Find form IDs
        </button>
    
        <p>The ID of all the forms is: </p>
        
        <div class = "ids"></div>
        
        <script> 
            function findFormIDs() {
                let final = '';
                let collection = document.forms;
    
                // Run a loop upto the number of
                // forms in the collection
                for (let i = 0; i < collection.length; i++) {
    
                    // Add each form id to the final list
                    final += `<li> ${collection[i].id} </li>`;
                }
                
                // Replace the inner HTML of the 
                // ID div to show the list
                document.querySelector(".ids").innerHTML = final;
            } 
        </script>
    </body>
</html>

Output:

Before Click on the button:

Find all form IDs - before

After Click on the button:

Find all form IDs - after

Example 3:

html

<!DOCTYPE html>
<html>
<head>
    <title>HTML | DOM forms Collection
</title>
</head>

<body>
    <h1 style="color:green">GeeksForGeeks</h1>
    <h2>DOM document.forms Property</h2>

    <form id="personal-info">
        <h3>Personal Information Area</h3>
        Name: <input type="text">
    </form>
    <form id="home-info">
        <h3>Home Address Information Area</h3>
        Address: <input type="text">
    </form>
    <form id="delivery-info">
        <h3>Delivery Type Area</h3>
        Delivery Speed: <input type="text">
    </form>

    <p>
     Click the button below to find by form
     ID and get the name field:
    </p>
    <button onclick="returnForm()">
     Find by form ID
    </button>
    <p>The text in the name field is: </p>
    <div class="name"></div>
    <script>
        function returnForm() {
            // find by id of 'personal-info'
            let collection = 
                     document.forms.namedItem("personal-info");

            // access the first element in the 
            //collection and find its value
            // in this case it would be the name field
            let name = collection[0].value;

            document.querySelector(".name").innerHTML = name;

        }
    </script>
</body>
</html>