The forms read-only property of the Document interface returns an HTMLCollection listing all the <form> elements contained in the document. 
   Note: Similarly, you can access a list of a form's component user input elements using the HTMLFormElement.elements property. 
  
 
Value
 An HTMLCollection object listing all of the document's forms. Each item in the collection is a HTMLFormElement representing a single <form> element. 
 If the document has no forms, the returned collection is empty, with a length of zero.
 
Examples
<!doctype html>
<html lang="en">
  <head>
    <title>document.forms example</title>
  </head>
  <body>
    <form id="robby">
      <input
        type="button"
        onclick="alert(document.forms[0].id);"
        value="robby's form" />
    </form>
    <form id="dave">
      <input
        type="button"
        onclick="alert(document.forms[1].id);"
        value="dave's form" />
    </form>
    <form id="paul">
      <input
        type="button"
        onclick="alert(document.forms[2].id);"
        value="paul's form" />
    </form>
  </body>
</html>
  
const selectForm = document.forms[index];
const selectFormElement = document.forms[index].elements[index];
  
<!doctype html>
<html lang="en">
  <head>
    <title>document.forms example</title>
  </head>
  <body>
    <form name="login">
      <input name="email" type="email" />
      <input name="password" type="password" />
      <button type="submit">Log in</button>
    </form>
    <script>
      const loginForm = document.forms.login; 
      loginForm.elements.email.placeholder = "[email protected]";
      loginForm.elements.password.placeholder = "password";
    </script>
  </body>
</html>
  
Specifications
Browser compatibility
 | 
Desktop | 
Mobile | 
 | 
Chrome | 
Edge | 
Firefox | 
Internet Explorer | 
Opera | 
Safari | 
WebView Android | 
Chrome Android | 
Firefox for Android | 
Opera Android | 
Safari on IOS | 
Samsung Internet | 
forms | 
1 | 
12 | 
1 | 
4 | 
≤12.1 | 
1 | 
4.4 | 
18 | 
4 | 
≤12.1 | 
1 | 
1.0 | 
 
See also