CSS:
.blue
{
width:200px;
height:200px;
background-color:blue;
color:#000000;
overflow:auto;
}
JavaScript:
function addChar() {
$('.blue').append('some text ');
}
HTML:
<div id='blue1' class="blue"></div><br />
<a href='javascript:void(0)' onclick='addChar()'>Add</a>
div id='blue1' has overflow property set to auto. I want to detect overflow when it happens.
$.fn.HasScrollBar = function() {
//note: clientHeight= height of holder
//scrollHeight= we have content till this height
var _elm = $(this)[0];
var _hasScrollBar = false;
if ((_elm.clientHeight < _elm.scrollHeight) || (_elm.clientWidth < _elm.scrollWidth)) {
_hasScrollBar = true;
}
return _hasScrollBar;
}
/// this is my solution
$.fn.hasOverflow = function() {
var $this = $(this);
var $children = $this.find('*');
var len = $children.length;
if (len) {
var maxWidth = 0;
var maxHeight = 0
$children.map(function(){
maxWidth = Math.max(maxWidth, $(this).outerWidth(true));
maxHeight = Math.max(maxHeight, $(this).outerHeight(true));
});
return maxWidth > $this.width() || maxHeight > $this.height();
}
return false;
};
Example:
var $content = $('#content').children().wrapAll('<div>');
while($content.hasOverflow()){
var size = parseFloat($content.css('font-size'), 10);
size -= 1;
$content.css('font-size', size + 'px');
}
One-liner solution to the specific question:
var elt, hasOverflow = (elt = $('#blue1')).innerWidth() > elt[0].scrollWidth;
Just wanted to golf a bit. :]
(Note: This is only for horizontal overflow detection; it's trivial to add vertical overflow detection as well.)
As far as I know you will have to compare the width/clientWidth and height/clientHeight in your addChar() function. When that changes you've got scrollbars (unless you moddify the dimensions somewhere else ...)
Something like this:
function addChar () {
var blueEl = $( '.blue' );
blueEl.append ( 'some text ' );
if ( blueEl.width () !== blueEl[0].clientWidth || blueEl.height () !== blueEl[0].clientHeight ) {
// element just got scrollbars
}
}
$.fn.overflows = function() { return ($(this).width() !== this.clientWidth || $(this).height() !== this.clientHeight); };The only way I can think of is to create a nested DIV and compare the outer div height with the inner div. If you don't want to modify existing markup you can append it using jQuery like this:
var outer = $('.blue'),
inner = $('<div>').appendTo(outer);
function addChar() {
inner.append('some text ');
if (inner.height() > outer.height()) {
console.log('overflowed');
}
}
jQuery.fn.preventOverflow = function(){
return this.each(function(){
var defaultDisplay = $(this).css('display');
var defaultHeight = $(this).height();
$(this).css('display', 'table');
var newHeight = $(this).height();
$(this).css('display', defaultDisplay);
if(newHeight > defaultHeight){
$(this).height(newHeight);
}
});
};
$('.query').preventOverflow();
here i'm just preventing the height, but i think this method can be used to width too.
You can check the element's scrollWidth and/or scrollHeight properties against its clientWidth and/or clientHeight.
Note that this doesn't actually require jQuery.
clientWidth doesn't always act in a standard, cross-browser way and isn't part of the W3C standard, although it seems to have a lot of support.I used Luka's answer until I realised it was comparing each child individually. It didn't work since it doesn't calculate the dimensions of the content of a DOM node, just each child individually. I used the scrollHeight property of DOM nodes instead:
(function($) {
$.fn.hasOverflow = function() {
var $this = $(this);
return $this[0].scrollHeight > $this.outerHeight() ||
$this[0].scrollWidth > $this.outerWidth();
};
})(jQuery);
EDIT: Fixed a bug caused by using .height() which doesn't take padding into account.
Here's a plugin i wrote, which might come in handy if you want to find out if an element is overflown or not: https://github.com/ZetaSoftware/jquery-overflown-plugin.
With this plugin, in the original example, you could just do: $("#blue1").overflown() to find out of children of #blue1 are overflowing.
Thought I should add an improved solution based on Praveen's answer.
This improvement allows to check for width, height or both. Hence the name $.hasOverflow so thanks Luka as well. The ternary operator makes it a little more expressive and clear.
/**
* @param {Boolean} x overflow-x
* @param {Boolean} y overflow-y
*/
$.fn.hasOverflow = function (x, y) {
var el = $(this).get(0),
width = el.clientWidth < el.scrollWidth,
height = el.clientHeight < el.scrollHeight;
return !x
? !y
? width || height
: height
: width;
}
