Difference between value and placeholder

value：

If you want the default text to disappear after clicking the mouse, you need to add JS Of onfocus and onblur To achieve ,value and placeholder At the same time ,value It will cover placeholder The upper , Display only value The content of

placeholder：

stay input Tags only serve as placeholders , In the absence of value Will only show , And if you use placeholder Then there is no need for JS Of onfocus and onblur , It has its own function of gaining and losing focus