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>                     