How can you use JavaScript to read the content of a textbox and navigate an iframe to that content?

To read the content of a textbox and navigate an iframe to that content using JavaScript, you can first get the value of the textbox using the `value` property. Then, you can set the `src` attribute of the iframe to the value obtained from the textbox. ```javascript // Get the value of the textbox var textboxValue = document.getElementById('textboxId').value; // Set the src attribute of the iframe to the textbox value document.getElementById('iframeId').src = textboxValue; ```