Selecting all empty text fields in Jquery

问题

How can I find all text fields that have an empty value?

$(":text[value='']")  

gives a JavaScript error

I know I can do $(":text"), iterate through and return all fields with $(this).val()==''

I am looking for a cleaner method and using JQuery 1.3.1 It has to work if the element originally had a value when the page was loaded, and then the user cleared it. ($("#elem").attr('value') gives the original value in that place, though .val() works properly)

回答1:

Latest Answer: Upgrade to 1.3.2

Here are various tests I ran via FireBug on http://docs.jquery.com/Downloading_jQuery

Different jQuery versions are switched in at page-load with special greasemonkey scripts.

>>> jQuery.prototype.jquery
"1.3.2"
>>> jQuery(":text[value='']")
[input#jq-primarySearch]
Unknown pseudo-class or pseudo-element 'text'.
>>> jQuery(":text[value=]").get()
[input#jq-primarySearch]

>>> jQuery.prototype.jquery
"1.3.1"
>>> jQuery(":text[value='']")
Syntax error, unrecognized expression: value='']
>>> jQuery(":text[value=]").get()
[input#jq-primarySearch]

>>> jQuery.prototype.jquery
"1.3"
>>> jQuery(":text[value='']");
Object length=1 prevObject=Object context=document
Unknown pseudo-class or pseudo-element 'text'.
[Break on this error] undefined
>>> jQuery(":text[value=]").get()
[input#jq-primarySearch]

Note that 1.3 and 1.3.2 handle it properly ( albeit with Firefox sending an error ) but they still get the node right.

Alternatively: you could use the :text[value=] notation, which appears to work everywhere I tried it. Its just a bit suspect thats all.

( Ignore my Previous rantings, they're all bollocks, not having a good day -_-)

回答2:

I've just tried this and worked fine for me:

$(":text[value=]")

I just removed single quotes in selector.

回答3:

You were close. There's no assignment in jQuery selectors, so you only need a single '=':

$(":text[value='']")

回答4:

This seems to work for me

$(":text:not([value])")

回答5:

The following code does this:

1. Searches the form for inputfields and textareas
2. Checks if the text value is empty or not

3. gives the textfield/textarea a black background-color to prove this works

   $('form').find("input[type=text], input[type=password], textarea").each(function(ev)
   {
   
   if(!$(this).val())
   {
      $(this).css("background-color","black");
   }
   
   });
   

回答6:

Shot in the dark as I haven't tested it, but does this work:

$(":text:empty")

来源：https://stackoverflow.com/questions/635240/selecting-all-empty-text-fields-in-jquery