javascript - Show placeholder text in empty input fields - Stack Overflow

How it is possible that during onfocus (on input field) input default value seen like it is disabled but on input field could be written anything like default value isn't exists ?

here is simple html =>

<input type="text" id="x">

and javascript =>

document.getElementById("x").onfocus = function(){
this.style.opacity = 0.5;
}

but I couldn't do what I want.

How it is possible that during onfocus (on input field) input default value seen like it is disabled but on input field could be written anything like default value isn't exists ?

here is simple html =>

<input type="text" id="x">

and javascript =>

document.getElementById("x").onfocus = function(){
this.style.opacity = 0.5;
}

but I couldn't do what I want.

• javascript
• css

Share Follow edited Jul 11, 2012 at 12:31 CharlesB 90.6k2929 gold badges201201 silver badges228228 bronze badges asked Jul 10, 2012 at 21:17 nanobashnanobash 5,50077 gold badges4040 silver badges5656 bronze badges 1

• I've tried a lot you know , and just do not written because it is really very simple , but can't solved it. I'll updated my question and please help if you can – nanobash Commented Jul 10, 2012 at 21:20

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3 Answers 3

Sorted by: Reset to default 8

With "HTML5", new functionality and attributes have been introduced for form-Elements (such as built-in form-validation for example)

One of those is the placeholder - attribute. It shows a specified text on empty input-Fields that will be hidden, after a user starts to fill text in the field. The HTML-Markup looks like this:

<input type="text" name="first_name" placeholder="Fill in your name">

This feature is not supported by all browsers yet (you can check patibility on caniuse.

In your code, you can check for patibility with a simple function:

var placeHolderSupport = ('placeholder' in document.createElement('input'));

For older browsers, you would need to write a fallback JavaScript - Function, that reads this attribute and implement the behaviour yourselve. There are some blog-posts about this around the web, like one from David Walsh, that could help you with this.

edit:

I stumbled over this gist by Hagenburger (according blog-post), that should implement the behaviour you want to achieve for old browsers too. Note: it's jQuery - code, not sure if you are using it, but even if not, it should give you an idea, what to do.

So, given the patibility - check from above:

if(!placeHolderSupport){
    //gist code here (not sure if i'm allowed to copy this into my answer)
}

Like that, the native placeholder-implementation of the browser would be used, if it exists, otherwise, the JavaScript-function would take care of this.

update 09/11/2012

SO-User and Moderator ThiefMaster just pointed out a better and newer jQuery-plugin by Mathias Bynens, that already has built-in check for placeholder - support. Surely a better way to implement the placeholder-fallback than the gist I posted:

jQuery Placeholder at github

<input type="text" value="blah" name="Email"
 id="Email" onblur="this.value = 'blah';"
 onfocus="this.value = 'blah';" />

<input type="text" data-placeholder="Name" />


$(function(){
    $('input').each(function(){
    if($(this).val() == ''){
        $(this).val($(this).data('placeholder'));
    }
});

});
$('input').focusin(function(){
    if($(this).val() == $(this).data('placeholder')){
        $(this).val('');
    }
}).focusout(function(){    
    if($(this).val().length < 0){
        $(this).val($(this).data('placeholder'));
    }
})​;​

See example quick and dirty example here.