极力推荐10个短小实用的JavaScript代码段

 function isValidDate(value, userFormat) {

 // Set default format if format is not provided
 userFormat = userFormat || 'mm/dd/yyyy';

 // Find custom delimiter by excluding
 // month, day and year characters
 var delimiter = /[^mdy]/.exec(userFormat)[0];

 // Create an array with month, day and year
 // so we know the format order by index
 var theFormat = userFormat.split(delimiter);

 // Create array from user date
 var theDate = value.split(delimiter);

 function isDate(date, format) {
 var m, d, y, i = 0, len = format.length, f;
 for (i; i < len; i++) {
 f = format[i];
 if (/m/.test(f)) m = date[i];
 if (/d/.test(f)) d = date[i];
 if (/y/.test(f)) y = date[i];
 }
 return (
 m > 0 && m < 13 &&
 y && y.length === 4 &&
 d > 0 &&
 // Check if it's a valid day of the month
 d <= (new Date(y, m, 0)).getDate()
 );
 }

 return isDate(theDate, theFormat);
} 

 var getMaxHeight = function ($elms) {
 var maxHeight = 0;
 $elms.each(function () {
 // In some cases you may want to use outerHeight() instead
 var height = $(this).height();
 if (height > maxHeight) {
  maxHeight = height;
 }
 });
 return maxHeight;
}; 

 function highlight(text, words, tag) {

 // Default tag if no tag is provided
 tag = tag || 'span';

 var i, len = words.length, re;
 for (i = 0; i < len; i++) {
 // Global regex to highlight all matches
 re = new RegExp(words[i], 'g');
 if (re.test(text)) {
  text = text.replace(re, '<'+ tag +' class="highlight">$&</'+ tag +'>');
 }
 }

 return text;
} 

 function unhighlight(text, tag) {
 // Default tag if no tag is provided
 tag = tag || 'span';
 var re = new RegExp('(<'+ tag +'.+?>|<\/'+ tag +'>)', 'g');
 return text.replace(re, '');
} 

 $('p').html( highlight(
 $('p').html(), // the text
 ['foo', 'bar', 'baz', 'hello world'], // list of words or phrases to highlight
 'strong' // custom tag
)); 

 $.fn.animateText = function(delay, klass) {

 var text = this.text();
 var letters = text.split('');

 return this.each(function(){
 var $this = $(this);
 $this.html(text.replace(/./g, '<span class="letter">$&</span>'));
 $this.find('span.letter').each(function(i, el){
  setTimeout(function(){ $(el).addClass(klass); }, delay * i);
 });
 });

}; 

 $.fn.fadeAll = function (ops) {
 var o = $.extend({
 delay: 500, // delay between elements
 speed: 500, // animation speed
 ease: 'swing' // other require easing plugin
 }, ops);
 var $el = this;
 for (var i=0, d=0, l=$el.length; i<l; i++, d+=o.delay) {
 $el.eq(i).delay(d).fadeIn(o.speed, o.ease);
 }
 return $el;
} 

 function excerpt(str, nwords) {
 var words = str.split(' ');
 words.splice(nwords, words.length-1);
 return words.join(' ') +
 (words.length !== str.split(' ').length ? '…' : '');
} 

 function isBreakPoint(bp) {
 // The breakpoints that you set in your css
 var bps = [320, 480, 768, 1024];
 var w = $(window).width();
 var min, max;
 for (var i = 0, l = bps.length; i < l; i++) {
 if (bps[i] === bp) {
  min = bps[i-1] || 0;
  max = bps[i];
  break;
 }
 }
 return w > min && w <= max;
} 

 if ( isBreakPoint(320) ) {
 // breakpoint at 320 or less
}
if ( isBreakPoint(480) ) {
 // breakpoint between 320 and 480
}
… 

 $(element)
 .data('counter', 0) // begin counter at zero
 .click(function() {
  var counter = $(this).data('counter'); // get
  $(this).data('counter', counter + 1); // set
  // do something else...
 }); 

 function embedYouku(link, ops) {

 var o = $.extend({
 width: 480,
 height: 320,
 params: ''
 }, ops);

 var id = /\?v\=(\w+)/.exec(link)[1];

 return '<embed allowFullScreen="true" id="embedid" quality="high" width="'+o.width+'" height="'+o.height+'" align="middle" allowScriptAccess="always" type="application/x-shockwave-flash" src="'+id+'?'+o.ops'"';
} 

 embedYouku(
 'http://static.youku.com/v/swf/qplayer.swf', 
 {'winType=adshow&VideoIDS=XMTE3NzQ0NTky&isAutoPlay=false&isShowRelatedVideo=false'}
); 

 function makeMenu(items, tags) {

 tags = tags || ['ul', 'li']; // default tags
 var parent = tags[0];
 var child = tags[1];

 var item, value = '';
 for (var i = 0, l = items.length; i < l; i++) {
 item = items[i];
 // Separate item and value if value is present
 if (/:/.test(item)) {
  item = items[i].split(':')[0];
  value = items[i].split(':')[1];
 }
 // Wrap the item in tag
 items[i] = '<'+ child +' '+
  (value && 'value="'+value+'"') +'>'+ // add value if present
  item +'</'+ child +'>';
 }

 return '<'+ parent +'>'+ items.join('') +'</'+ parent +'>';
} 

 // Dropdown select month
makeMenu(
 ['January:JAN', 'February:FEB', 'March:MAR'], // item:value
 ['select', 'option']
);

// List of groceries
makeMenu(
 ['Carrots', 'Lettuce', 'Tomatos', 'Milk'],
 ['ol', 'li']
);