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unobtrusive “default” text in input WITHOUT jQuery

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攒了一身酷
攒了一身酷 2021-01-16 22:15

i\'m trying to write unobtrusive default/placeholder text in input (actually, relatively placed label over input, which hides on onFocus

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7条回答
  • 陌清茗
    2021-01-16 22:37 
    <input name="test" type="text" id="test" value="testValue" />

<script type="text/javascript">
 var myInput = document.getElementById("test");
 myInput.onfocus = function() {
   this.value = '';
 }
  myInput.onblur = function() {
   if(this.value == '') this.value = "testValue";
}
</script>
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  • 执念已碎
    2021-01-16 22:40

    I think that you need something like this:

    <input type="text" onfocus="if (this.value == this.getAttribute('mydefaulttext')) this.value = '';" onblur="if (this.value == '') this.value = this.getAttribute('mydefaulttext');" mydefaulttext="click here..." value="click here..."/>

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  • 遇见更好的自我
    2021-01-16 22:48

    I suggest you use jQuery

    jQuery is nothing more than a cross-browser library that makes it easier for developers to achieve something and not worry about browser particularities. And when you load it once (it's rather small) it's cached so I wouldn't worry because it will save you lots of development/testing time later.

    No? Then do it manually but make it more reusable

    But if you do decide to do something manually you can always use regular Javascript and manipulate DOM as you wish. You best friends in this case would of course be (as Andrew pointed out):

    • getElementById() and
    • getElementsByTagName()

    functions, but since you'll be manipulating DOM and styles, make sure you test your code against all common browsers. If you use custom attributes on INPUT elements it's good to use the second function, so you'll attach additional functionality to all inputs at once and only to those that define that particular custom attribute like:

    <input type=text id="inputX" name="inputX" placeholder="Enter something">

    Your script would then get all inputs and you'd check for the custom attribute existance and attach events to those elements that do define that attribute. This way you won't depend on IDs and make your code universal so you can reuse it app wide. Or even on other projects.

    Just a sidenote: Andrew's example works somehow differently than what you said would like to do (using labels), but I suggest you use the same approach, because you'll be running scripts anyway. For the sake of unobtrusiveness make sure that you set default content using Javascript so default values and styles on textboxes won't be set for those users that are not running Javascript.

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  • 离开以前
    2021-01-16 22:48

    This is how I would do it, without JQuery. It grays out the control when it shows the default text, and allows entering the default text if need be. The "title" tag will fallback to a tooltip for people who disable JavaScript:

    <html>
<body>
<input type="text" value="" title="default text"  />

<script type="text/javascript">
function DefaultInput(e) {
    // Get the elements
    this.e = e
    this.d = e.title
    this.s = e.style
    e.removeAttribute('title') // remove the tooltip
    e.value = '' // IE cached value remove HACK!

    // Bind the events
    e.onblur = this.bind(this.onblur)
    e.onfocus = this.bind(this.onfocus)

    // Show the initial value in gray
    this.onblur()
}

DefaultInput.prototype = {
    bind: function(f) {
        // Return `f` so it's always called as an object of DefaultInput
        var o = this
        return function(){
            f.apply(o, arguments)
        }
    },

    onblur: function() {
        // Gray out my value and show the default text if my value's blank
        if (!this.h && !this.e.value) {
            this.s.color = 'gray'
            this.e.value = this.d
            this.h = true // true -> help text displayed
                          // false -> help text hidden/user entered value
        }
    },

    onfocus: function() {
        // Make the text black and blank the text if in "help" mode
        if (this.h) {
            this.s.color = 'black'
            this.e.value = ''
            this.h = false
        }
    }   
}

// Make sure the page is loaded before 
// running for twitchy browsers like IE
window.onload = function() {
    // Add defaults for all text input elements which have a `title`
    var L = document.getElementsByTagName('input')
    for (var i=0; i<L.length; i++) {
        var e = L[i]
        if (e.type=='text' && 'title' in e)
            new DefaultInput(e)
    }
}
</script>
</body>

    EDIT: Cleared up the comments a bit, fixed some IE bugs and made it so it looks for <input> tags with title's to make it so different pages have less conversion time rather than individually intitializing the input controls ;-)

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  • 攒了一身酷
    2021-01-16 22:49

    You can use jQuery and still be unobtrusive and use the ability of HTML5 Browsers, make your input like this:

    <input type="whatever" placeholder="Your Default Text"/>

    I user Modernizr to check the html5 capabilities of the browser and if the browser doesn't understand the placeholder attribute than I use this little javascript to emulate this function.

    if (!Modernizr.input.placeholder) {
  $('input').each(function(){
    var obj = $(this);
    var placeholder = obj.attr('placeholder');
    if (placeholder) {
      obj.val(placeholder);
      obj.focus(function(){
        var obj2 = $(this);
        if (obj2.val() == obj2.attr('placeholder')) obj2.val('');
      });
      obj.blur(function(){
        var obj2 = $(this);
        if (obj2.val() == '') obj2.val(obj2.attr('placeholder'));
      });
    }
  });
}

    It is unobtrusive, because you don't need any javascript in your html code. the function above can easily changed if you want to use any other framework. I wouldn't use a solution without any Framework, because the frameworks do a great job in working around the incompatibilities between browsers.

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  • 清歌不尽
    2021-01-16 22:52

    Here's how I do:

    Online Working Example

    http://jsbin.com/ehivo3 (source code)

    HTML

    <input type="text" name="myfield" id="myfield" value="Please, fill my field!!!" />

    jQuery

    $(document).ready(function() {
  // Handle each input on focus() and blug()
  $('input[type="text"]').each(function() {
    $(this)
      // Store the default value internally
      // Don't use .val() because browser autofill will poison it
      .data('defaultValue', $(this).attr('value'))
      // Handle the focus() (when you enter the field)
      .focus(function() {
        if ($(this).val() == $(this).data('defaultValue'))
          $(this).val('');
      })
      // Handle the blur() (when you leave the field)
      .blur(function() {
        if ($(this).val() == '')
          $(this).val($(this).data('defaultValue'));
      });
  });

  // Clear all fields with "default value" on submit
  $('form').submit(function() {
    $('input[type="text"]', $(this)).each(function() {
      // If the input still with default value, clean it before the submit
      if ($(this).val() == $(this).data('defaultValue'))
        $(this).val('');
    });
  });
});

    And that's all! No invalid or extra attributes, valid markup and all handled in your jQuery file. :)

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