jQuery值属性选择器未返回正确的元素数

Question

I have a programme that generates a count after the key is up. JQuery Code:

$('.today').keyup(function() {
    var Presents = $('input[value="/"]:visible');
    $("#counter").html( "Present: " + Presents.length );
});

HTML:

<input type="text" id="1" name="1" class="today" value="/">
<input type="text" id="2" name="2" class="today" value="/">
<input type="text" id="3" name="3" class="today" value="/">
<p id="counter"></p>

The counter tag will display 3 after first key up. When i change the value in the text boxes the value does not change in the counter box. EG when i chance the value of text box 3 to x the

tag should now contain the number 2. Currently this does not change.

Answer 1

You are using an attribute selector, but when you change the input value, it won't change the attribute; just the property. You can use filter() to get what you need:

$('.today').keyup(function() {
    var Presents = $('input:visible').filter(function(){
      return this.value == "/";  
    });
    $("#counter").html( "Present: " + Presents.length );
});

JSFiddle

If you needed to update the attribute itself, you can do simply by adding the following to the top of your event handler:

$(this).attr('value',this.value);

JSFiddle

But that seems pretty messy to me. Also, I believe filter() will be faster than an attribute selector anyway.