Hey Jeevika, you can use following automation script to select a date from a datepicker div in Webdriver:
driver = new FirefoxDriver();
driver.get("http://jqueryui.com/datepicker/");
driver.switchTo().frame(0);
driver.manage().timeouts().implicitlyWait(60, TimeUnit.SECONDS);
driver.findElement(By.id("datepicker")).click();
driver.manage().timeouts().implicitlyWait(60, TimeUnit.SECONDS);
WebElement dateWidget = driver.findElement(By.id("ui-datepicker-div"));
List rows=dateWidget.findElements(By.tagName("tr"));
List columns=dateWidget.findElements(By.tagName("td"));
for (WebElement cell: columns){
//Select 10th Date
if (cell.getText().equals("10")){
cell.findElement(By.linkText("10")).click();
break;
}
}