HTML TextArea defaultValue Property: Textarea Default Value

HTML TextArea defaultValue Property: Setting the Default Text

The HTML <textarea> element is used to create multi-line text input areas in web forms. The defaultValue property in JavaScript allows you to set or retrieve the initial content of a <textarea> element. This is different from the value property, which reflects the current content that the user can change.

What is the defaultValue Property?

The defaultValue property specifies the initial value of a <textarea> field when the page loads. It’s particularly useful for providing default instructions, sample text, or pre-filled data in a form.

Syntax

Getting the Default Value

let defaultText = textAreaElement.defaultValue;

Setting the Default Value

textAreaElement.defaultValue = "Your default text here";

Usage Notes

• Initial Content: defaultValue sets the text that appears when the page is first loaded.
• User Changes: Modifying defaultValue in JavaScript does not change the text currently displayed in the <textarea> element.
• Resetting the Field: The defaultValue is used when a form is reset.

Practical Examples

Let’s explore how to use the defaultValue property with some practical examples.

Example 1: Setting a Default Value on Page Load

In this example, we set the defaultValue of a <textarea> element when the page loads.

<textarea id="defaultTextArea1" rows="4" cols="50"></textarea>
<script>
  const textArea1 = document.getElementById("defaultTextArea1");
  textArea1.defaultValue = "Enter your comments here...";
</script>

This code will render a <textarea> field with the default text “Enter your comments here…”.

Example 2: Retrieving the Default Value

This example demonstrates how to retrieve the default value of a <textarea> element using JavaScript.

<textarea id="defaultTextArea2" rows="4" cols="50">
  This is the initial default value.
</textarea>
<p id="defaultValueDisplay"></p>
<script>
  const textArea2 = document.getElementById("defaultTextArea2");
  const displayParagraph = document.getElementById("defaultValueDisplay");
  const defaultValue = textArea2.defaultValue;
  displayParagraph.textContent = "Default Value: " + defaultValue;
</script>

Here, the script retrieves the defaultValue and displays it in a paragraph element.

Example 3: Using defaultValue in a Form

This example shows how the defaultValue is used when a form is reset.

<form id="myForm">
  <textarea id="defaultTextArea3" rows="4" cols="50">
    Initial default text.
  </textarea>
  <br />
  <button type="reset">Reset Form</button>
</form>
<script>
  const form = document.getElementById("myForm");
  form.addEventListener("reset", () => {
    const textArea3 = document.getElementById("defaultTextArea3");
    console.log("TextArea value after reset:", textArea3.value);
  });
</script>

When the “Reset Form” button is clicked, the <textarea> will revert to its defaultValue.

Example 4: Dynamically Setting defaultValue

In this example, we dynamically set the defaultValue of a <textarea> element based on a user interaction.

<textarea id="defaultTextArea4" rows="4" cols="50"></textarea>
<br />
<button id="setDefaultButton">Set Default Text</button>
<script>
  const textArea4 = document.getElementById("defaultTextArea4");
  const setDefaultButton = document.getElementById("setDefaultButton");

  setDefaultButton.addEventListener("click", () => {
    textArea4.defaultValue = "This text was set dynamically!";
  });
</script>

Clicking the “Set Default Text” button will set the defaultValue of the <textarea> element. Note that this does not change the current value of the textarea, only the underlying default.

Example 5: Comparing value and defaultValue

This example illustrates the difference between the value and defaultValue properties.

<textarea id="defaultTextArea5" rows="4" cols="50">
  Initial Value
</textarea>
<br />
<button id="showValuesButton">Show Values</button>
<p id="valuesDisplay"></p>
<script>
  const textArea5 = document.getElementById("defaultTextArea5");
  const showValuesButton = document.getElementById("showValuesButton");
  const valuesDisplay = document.getElementById("valuesDisplay");

  showValuesButton.addEventListener("click", () => {
    const currentValue = textArea5.value;
    const defaultValue = textArea5.defaultValue;
    valuesDisplay.textContent =
      "Current Value: " + currentValue + ", Default Value: " + defaultValue;
  });
</script>

This code will display the current value (which can be modified by the user) and the default value of the <textarea> element.

Browser Support

The defaultValue property is supported by all major browsers, including:

• Chrome
• Firefox
• Safari
• Edge
• Opera

Tips and Best Practices

• Use for Initial Hints: Use defaultValue to provide initial instructions or sample text to guide users.
• Distinguish from value: Remember that defaultValue is for the initial state, while value reflects the current state.
• Form Reset Behavior: Keep in mind that the defaultValue is used when a form is reset.

Conclusion

The defaultValue property of the HTML <textarea> element is a useful tool for setting the initial content of a text area. Understanding how to use this property can help you create more user-friendly and functional web forms. By providing default text, you can guide users and ensure that forms are properly filled out.