字段中保存的值的Javascript状态？

Question

I'm using a javascript library to move field labels into the field itself. When the user starts typing in the field, they fade out. However, when the user has saved their username/password in the fields, the library isn't smart enough not to put the labels in the fields, so the text of the label is overrun with the username or the obfuscated password.

Is there a state of the pre-populated fields I could query with javascript to selectively disable moving the labels into the fields?

Edit this is the library that I'm using: In-Field Labels jQuery Plugin

I see that there has been a vote to close this question because it is unclear. Let me try to be more clear. When the page loads, there is a saved username and password in the username and password fields. I am wondering if there is some property on these fields that will tell me if they are populated with saved values when the page finishes loading. If this is unclear please ask a clarifying question.

The reason I want to know this is because I am using a javascript library that puts a field's label visually within its field, so you get [Username____] instead of Username [________] . The problem is when the browser has saved the username, then the text "Username" in the field runs over the saved username also in the field. I want to stop the moving of the field label into the field only if there is a value already in it. So I am looking for a way I can tell if the field is pre-populated.

Answer 1

I think what you are talking about is a PlaceHolder attribute :

A hint to the user of what can be entered in the control . The placeholder text must not contain carriage returns or line-feeds. This attribute applies when the value of the type attribute is text, search, tel, url or email; otherwise it is ignored.

See this JSFiddle :

<input type="text" placeholder="label"/>

For a cross browser compatibility, see this plugin : https://github.com/mathiasbynens/jquery-placeholder