Getting Error Message : org.openqa.selenium.InvalidElementStateException: Element must not be hidden, disabled or read-only

Reason : if object hidden, then webdriven unable to enter the text. so we need to enable the text by using javascriptexecutor, then will enter the script

Solution :

WebDriver driver = new FirefoxDriver();
JavascriptExecutor jse = (JavascriptExecutor)driver;
jse.executeScript("document.getElementById('mini-7').setAttribute('type', 'text');");
driver.findElement(By.cssSelector("#mini-7 > input.mini-textbox-input")).clear();
driver.findElement(By.cssSelector("#mini-7 > input.mini-textbox-input")).sendKeys("yy");