vendor/assets/javascripts/elastic.js
/**
* @name Elastic
* @descripton Elastic is jQuery plugin that grow and shrink your textareas automatically
* @version 1.6.11
* @requires jQuery 1.2.6+
*
* @author Jan Jarfalk
* @author-email jan.jarfalk@unwrongest.com
* @author-website http://www.unwrongest.com
*
* @licence MIT License - http://www.opensource.org/licenses/mit-license.php
*/
(function($){
jQuery.fn.extend({
elastic: function() {
// We will create a div clone of the textarea
// by copying these attributes from the textarea to the div.
var mimics = [
'paddingTop',
'paddingRight',
'paddingBottom',
'paddingLeft',
'fontSize',
'lineHeight',
'fontFamily',
'width',
'fontWeight',
'border-top-width',
'border-right-width',
'border-bottom-width',
'border-left-width',
'borderTopStyle',
'borderTopColor',
'borderRightStyle',
'borderRightColor',
'borderBottomStyle',
'borderBottomColor',
'borderLeftStyle',
'borderLeftColor'
];
return this.each( function() {
// Elastic only works on textareas
if ( this.type !== 'textarea' ) {
return false;
}
var $textarea = jQuery(this),
$twin = jQuery('<div />').css({
'position' : 'absolute',
'display' : 'none',
'word-wrap' : 'break-word',
'white-space' :'pre-wrap'
}),
lineHeight = parseInt($textarea.css('line-height'),10) || parseInt($textarea.css('font-size'),'10'),
minheight = parseInt($textarea.css('height'),10) || lineHeight*3,
maxheight = parseInt($textarea.css('max-height'),10) || Number.MAX_VALUE,
goalheight = 0;
// Opera returns max-height of -1 if not set
if (maxheight < 0) { maxheight = Number.MAX_VALUE; }
// Append the twin to the DOM
// We are going to meassure the height of this, not the textarea.
$twin.appendTo($textarea.parent());
// Copy the essential styles (mimics) from the textarea to the twin
var i = mimics.length;
while(i--){
$twin.css(mimics[i].toString(),$textarea.css(mimics[i].toString()));
}
// Updates the width of the twin. (solution for textareas with widths in percent)
function setTwinWidth(){
var curatedWidth = Math.floor(parseInt($textarea.width(),10));
if($twin.width() !== curatedWidth){
$twin.css({'width': curatedWidth + 'px'});
// Update height of textarea
update(true);
}
}
// Sets a given height and overflow state on the textarea
function setHeightAndOverflow(height, overflow){
var curratedHeight = Math.floor(parseInt(height,10));
if($textarea.height() !== curratedHeight){
$textarea.css({'height': curratedHeight + 'px','overflow':overflow});
}
}
// This function will update the height of the textarea if necessary
function update(forced) {
// Get curated content from the textarea.
var textareaContent = $textarea.val().replace(/&/g,'&').replace(/ {2}/g, ' ').replace(/<|>/g, '>').replace(/\n/g, '<br />');
// Compare curated content with curated twin.
var twinContent = $twin.html().replace(/<br>/ig,'<br />');
if(forced || textareaContent+' ' !== twinContent){
// Add an extra white space so new rows are added when you are at the end of a row.
$twin.html(textareaContent+' ');
// Change textarea height if twin plus the height of one line differs more than 3 pixel from textarea height
if(Math.abs($twin.height() + lineHeight - $textarea.height()) > 3){
var goalheight = $twin.height()+lineHeight;
if(goalheight >= maxheight) {
setHeightAndOverflow(maxheight,'auto');
} else if(goalheight <= minheight) {
setHeightAndOverflow(minheight,'hidden');
} else {
setHeightAndOverflow(goalheight,'hidden');
}
}
}
}
// Hide scrollbars
$textarea.css({'overflow':'hidden'});
// Update textarea size on keyup, change, cut and paste
$textarea.bind('keyup change cut paste', function(){
update();
});
// Update width of twin if browser or textarea is resized (solution for textareas with widths in percent)
jQuery(window).bind('resize', setTwinWidth);
$textarea.bind('resize', setTwinWidth);
$textarea.bind('update', update);
// Compact textarea on blur
$textarea.bind('blur',function(){
if($twin.height() < maxheight){
if($twin.height() > minheight) {
$textarea.height($twin.height());
} else {
$textarea.height(minheight);
}
}
});
// And this line is to catch the browser paste event
$textarea.bind('input paste',function(e){ setTimeout( update, 250); });
// Run update once when elastic is initialized
update();
});
}
});
})(jQuery);