分享10个超实用的jQuery代码片段

JavaScript技术    2013-07-11 23:57  

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!

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;
	});

});

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/20864b59-a995-4318-a242-b3038f83f2c3.htm

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;
		}
	});

});

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/5a2271a5-f363-4b34-8d2f-f0ad03121ced.htm

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);
});

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;
});

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/5ae6bca8-b12b-48b8-861a-8d9ab09e6641.htm

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);

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/ac7c5175-9282-41c0-a766-c56707946c7b.htm

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。

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 = '<h2>' 
				      + data.posts[i].title
				      + '</h2>'
				      + '<p>'
				      + data.posts[i].excerpt
				      + '</p>'
				      + '<a href="'
				      + data.posts[i].url
				      + '" title="Read '
				      + data.posts[i].title
				      + '">Read ></a>';
 
			//Append the body with the string
			$('body').append(strPost);
 
		}
	}
 
}
 
//Fire off the function in your document ready
$(document).ready(function(){
	parseJson();				   
});

jQuery实现让整个div可以被点击

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

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/4bfb3dce-1681-470c-b47a-7490df12f3b0.htm

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 = $("<img>").attr("src", nextimage).load(function(){
     $('div').append(img);
    });
  }, 100);
});

运行代码:

GBdebug在线调试地址:http://www.gbin1.com/gb/debug/b1a87e30-e33f-4369-92fc-55e8fd628816.htm

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!

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