9 个超实用的 jQuery 代码片段，来源于： http://www.iteye.com/news/28023

 

jQuery以其强大的功能和简单的使用成为了前端开发者最喜欢的JS类库，在这里我们分享一组实用的jQuery代码片段，希望大家喜欢！ 

1.  jQuery平滑回到顶端效果 

 

$(document).ready(function() {

	$("a.topLink").click(function() {
		$("html, body").animate({
			scrollTop: $($(this).attr("href")).offset().top + "px"
		}, {
			duration: 500,
			easing: "swing"
		});
		return false;
	});

});

2.  jQuery处理图片尺寸 

 

 

$(window).bind("load", function() {
	// 图片修改大小
	$('#imglist img').each(function() {
		var maxWidth = 120;
		var maxHeight = 120;
		var ratio = 0;
		var width = $(this).width();
		var height = $(this).height();
	
		if(width > maxWidth){
			ratio = maxWidth / width;
			$(this).css("width", maxWidth);
			$(this).css("height", height * ratio);
			height = height * ratio;
		}
      
		if(height > maxHeight){
			ratio = maxHeight / height;
			$(this).css("height", maxHeight);
			$(this).css("width", width * ratio);
			width = width * ratio;
		}
	});

});

3.  jQuery实现的滚动自动加载代码 

 

var loading = false;
$(window).scroll(function(){
	if((($(window).scrollTop()+$(window).height())+250)>=$(document).height()){
		if(loading == false){
			loading = true;
			$('#loadingbar').css("display","block");
			$.get("load.php?start="+$('#loaded_max').val(), function(loaded){
				$('body').append(loaded);
				$('#loaded_max').val(parseInt($('#loaded_max').val())+50);
				$('#loadingbar').css("display","none");
				loading = false;
			});
		}
	}
});

$(document).ready(function() {
	$('#loaded_max').val(50);
});

4.  jQuery测试密码强度 

 

 

$('#pass').keyup(function(e) {
     var strongRegex = new RegExp("^(?=.{8,})(?=.*[A-Z])(?=.*[a-z])(?=.*[0-9])(?=.*\W).*$", "g");
     var mediumRegex = new RegExp("^(?=.{7,})(((?=.*[A-Z])(?=.*[a-z]))|((?=.*[A-Z])(?=.*[0-9]))|((?=.*[a-z])(?=.*[0-9]))).*$", "g");
     var enoughRegex = new RegExp("(?=.{6,}).*", "g");
     if (false == enoughRegex.test($(this).val())) {
             $('#passstrength').html('More Characters');
     } else if (strongRegex.test($(this).val())) {
             $('#passstrength').className = 'ok';
             $('#passstrength').html('Strong!');
     } else if (mediumRegex.test($(this).val())) {
             $('#passstrength').className = 'alert';
             $('#passstrength').html('Medium!');
     } else {
             $('#passstrength').className = 'error';
             $('#passstrength').html('Weak!');
     }
     return true;
});

5.  jQuery实现的DIv高度保持一致 

 

 

var maxHeight = 0;

$("div").each(function(){
   if ($(this).height() > maxHeight) { maxHeight = $(this).height(); }
});

$("div").height(maxHeight);

6.  简单处理IE6上PNG格式文件 

 

 

$('.pngfix').each( function() {
   $(this).attr('writing-mode', 'tb-rl');
   $(this).css('background-image', 'none');
   $(this).css( 'filter', 'progid:DXImageTransform.Microsoft.AlphaImageLoader(src="path/to/image.png",sizingMethod="scale")');
});

将class=pngfix添加到需要处理的对象即可。 

 

 

7.  jQuery处理JSON 

 

function parseJson(){
	//Start by calling the json object, I will be using a 
        //file from my own site for the tutorial 
	//Then we declare a callback function to process the data
	$.getJSON('hcj.json',getPosts);
 
	//The process function, I am going to get the title, 
        //url and excerpt for 5 latest posts
	function getPosts(data){
 
		//Start a for loop with a limit of 5 
		for(var i = 0; i < 5; i++){
			//Build a template string of 
                        //the post title, url and excerpt
			var strPost = '

' + data.posts[i].title + '

' + '

' + data.posts[i].excerpt + '

' + 'Read >'; //Append the body with the string $('body').append(strPost); } } } //Fire off the function in your document ready $(document).ready(function(){ parseJson(); });
8.  jQuery实现让整个div可以被点击 

 

 

$(".myBox").click(function(){      window.location=$(this).find("a").attr("href");       return false; });

9.  jQuery实现的Facebook风格的图片预加载效果 

 

 

var nextimage = "http://www.gbtags.com/gb/networks/uploadimgthumb/55d67b14-fb25-45e7-acc8-211a41047ef0.jpg";
$(document).ready(function(){
  window.setTimeout(function(){
    var img = $("

").attr("src", nextimage).load(function(){ $('div').append(img); }); }, 100); }); [url=http://www.gbin1.com/gb/debug/b1a87e30-e33f-4369-92fc-55e8fd628816.htm]在线调试[/url]
希望大家喜欢这些实用的jQuery代码，如果你也有更多的jQuery代码片段，请与我们分享，谢谢！