通過xpath定位，xpath定位有N種寫法，列幾個常用寫法:

id:
driver.findElement(By.xpath("//*[@id='kw']"))
name:
driver.findElement(By.xpath("//*[@name='wd']"))
className:
driver.findElement(By.xpath("//input[@class='s_ipt']"))
css:
driver.findElement(By.xpath("/html/body/form/span/input"))
form：
driver.findElement(By.xpath("//form[@id='form']/span/input"))
id和name定位：
driver.findElement(By.xpath("//input[@id='kw' and @name='wd']"))