I've found that the best way to solve this is to use an <label>
and position it over the input area. This gives you:
- More aesthetic freedom
- Keeps your page semantic
- Allows you to gracefully degrade
- Doesn't cause problems by submitting the tooltip as the input value or have to worry about managing that problem
Here's a vanilla version since you asked for no framework. The markup shouldn't need to change, but you may need to adjust the CSS to work with your needs.
HTML:
<html>
<head>
<style>
label.magiclabel {
position: absolute;
padding: 2px;
}
label.magiclabel,
input.magiclabel {
width: 250px;
}
.hidden { display: none; }
</style>
<noscript>
<style>
/* Example of graceful degredation */
label.magiclabel {
position: static;
}
</style>
</noscript>
</head>
<body>
<label>This is not a magic label</label>
<form>
<label class="magiclabel" for="input-1">Test input 1</label>
<input class="magiclabel" type="text" id="input-1" name="input_1" value="">
<label class="magiclabel" for="input-2">Test input 2 (with default value)</label>
<input class="magiclabel" type="text" id="input-2" name="input_2" value="Default value">
</form>
<script src="magiclabel.js"></script>
</body>
</html>
vanilla-magiclabel.js
(function() {
var oldOnload = typeof window.onload == "function" ? window.onload : function() {};
window.onload = function() {
// Don't overwrite the old onload event, that's just rude
oldOnload();
var labels = document.getElementsByTagName("label");
for ( var i in labels ) {
if (
// Not a real part of the container
!labels.hasOwnProperty(i) ||
// Not marked as a magic label
!labels[i].className.match(/\bmagiclabel\b/i) ||
// Doesn't have an associated element
!labels[i].getAttribute("for")
) { continue; }
var associated = document.getElementById( labels[i].getAttribute("for") );
if ( associated ) {
new MagicLabel(labels[i], associated);
}
}
};
})();
var MagicLabel = function(label, input) {
this.label = label;
this.input = input;
this.hide = function() {
this.label.className += " hidden";
};
this.show = function() {
this.label.className = this.label.className.replace(/\bhidden\b/ig, "");
};
// If the field has something in it already, hide the label
if ( this.input.value ) {
this.hide();
}
var self = this;
// Hide label when input receives focuse
this.input.onfocus = function() {
self.hide();
};
// Show label when input loses focus and doesn't have a value
this.input.onblur = function() {
if ( self.input.value === "" ) {
self.show();
}
};
// Clicking on the label should cause input to be focused on since the `for`
// attribute is defined. This is just a safe guard for non-compliant browsers.
this.label.onclick = function() {
self.hide();
};
};
Vanilla demo
As you can see, about half of the code is wrapped up in the initialization in the window.onload
. This can be mitigated by using a framework. Here's a version using jQuery:
$(function() {
$("label.magiclabel[for]").each(function(index, label) {
label = $(label);
var associated = $("#" + label.attr("for"));
if ( associated.length ) {
new MagicLabel(label, associated);
}
});
});
var MagicLabel = function(label, input) {
// If the field has something in it already, hide the label
if ( input.val() !== "" ) {
label.addClass("hidden");
}
label.click(function() { label.addClass("hidden"); });
input.focus(function() { label.addClass("hidden"); });
input.blur(function() {
if ( input.val() === "" ) {
label.removeClass("hidden");
}
});
};
jQuery demo. The markup doesn't need to be changed, but of course you'll need to include the jQuery library.