分享50个使你成为高级javascript开发者的jQuery的代码开发技巧 - 第二部分

转载，但是忘记地址了。

26. 显示或者删除输入框的缺省值

//This snippet will show you how to keep a default value
//in a text input field for when a user hasn't entered in
//a value to replace it
swap_val = [];
$(".swap").each(function(i){
swap_val[i] = $(this).val();
$(this).focusin(function(){
if ($(this).val() == swap_val[i]) {
$(this).val("");
}
}).focusout(function(){
if ($.trim($(this).val()) == "") {
$(this).val(swap_val[i]);
}
});
});
<INPUT class="swap" value="Enter Username here.." type=text> 

 

27. 指定时间后自动隐藏或者关闭元素(1.4支持）

//Here's how we used to do it in 1.3.2 using setTimeout
setTimeout(function() {
$('.mydiv').hide('blind', {}, 500)
}, 5000);
//And here's how you can do it with 1.4 using the delay() feature (this is a lot like sleep)
$(".mydiv").delay(5000).hide('blind', {}, 500);

 

28. 动态创建元素到DOM

var newgbin1Div = $('');
newgbin1Div.attr('id','gbin1.com').appendTo('body');

 

29. 限制textarea的字符数量

jQuery.fn.maxLength = function(max){
this.each(function(){
var type = this.tagName.toLowerCase();
var inputType = this.type? this.type.toLowerCase() : null;
if(type == "input" && inputType == "text" || inputType == "password"){
//Apply the standard maxLength
this.maxLength = max;
}
else if(type == "textarea"){
this.onkeypress = function(e){
var ob = e || event;
var keyCode = ob.keyCode;
var hasSelection = document.selection? document.selection.createRange().text.length > 0 : this.selectionStart != this.selectionEnd;
return !(this.value.length >= max && (keyCode > 50 || keyCode == 32 || keyCode == 0 || keyCode == 13) && !ob.ctrlKey && !ob.altKey && !hasSelection);
};
this.onkeyup = function(){
if(this.value.length > max){
this.value = this.value.substring(0,max);
}
};
}
});
};
//Usage:
$('#gbin1textarea').maxLength(500);

 

30. 为函数创建一个基本测试用例

//Separate tests into modules.
module("Module B");
test("some other gbin1.com test", function() {
//Specify how many assertions are expected to run within a test.
expect(2);
//A comparison assertion, equivalent to JUnit's assertEquals.
equals( true, false, "failing test" );
equals( true, true, "passing test" );
});

 

31. 使用jQuery克隆元素

var cloned = $('#gbin1div').clone();

 

32. 测试一个元素在jQuery中是否可见

if($(element).is(':visible') == 'true') { //The element is Visible }

 

33. 元素屏幕居中

jQuery.fn.center = function () {
this.css('position','absolute');
this.css('top', ( $(window).height() - this.height() ) / +$(window).scrollTop() + 'px');
this.css('left', ( $(window).width() - this.width() ) / 2+$(window).scrollLeft() + 'px');return this;
}
//Use the above function as: $('#gbin1div').center();

 

34. 使用特定名字的元素对应的值生成一个数组

var arrInputValues = new Array();
$("input[name='table[]']").each(function(){
arrInputValues.push($(this).val());
});

 

35. 剔除元素中的HTML

(function($) {
$.fn.stripHtml = function() {
var regexp = /<("[^"]*"|'[^']*'|[^'">])*>/gi;
this.each(function() {
$(this).html(
$(this).html().replace(regexp,"")
);
});
return $(this);
}
})(jQuery);
//usage:
$('p').stripHtml();
36. 使用closest来得到父元素

$('#searchBox').closest('div');

 

37. 使用firebug来记录jQuery事件

// Allows chainable logging
// Usage: $('#someDiv').hide().log('div hidden').addClass('someClass');
jQuery.log = jQuery.fn.log = function (msg) {
if (console){
console.log("%s: %o", msg, this);
}
return this;
};

 

38. 点击链接强制弹出新窗口

jQuery('a.popup').live('click', function(){
newwindow=window.open($(this).attr('href'),'','height=200,width=150');
if (window.focus) {newwindow.focus()}
return false;
});

 

39. 点击链接强制打开新标签页

jQuery('a.newTab').live('click', function(){
newwindow=window.open($(this).href);
jQuery(this).target = "_blank";
return false;
});

 

40. 使用siblings()来处理同类元素

// Rather than doing this
$('#nav li').click(function(){
$('#nav li').removeClass('active');
$(this).addClass('active');
});
// Do this instead
$('#nav li').click(function(){
$(this).addClass('active')
.siblings().removeClass('active');
});

 

41. 选择或者不选页面上全部复选框

var tog = false; // or true if they are checked on load
$('a').click(function() {
$("input[type=checkbox]").attr("checked",!tog);
tog = !tog;
});

 

42. 基于输入文字过滤页面元素

//If the value of the element matches that of the entered text
//it will be returned
$('.gbin1Class').filter(function() {
return $(this).attr('value') == $('input#gbin1Id').val() ;
})

 

43. 取得鼠标的X和Y坐标

$(document).mousemove(function(e){
$(document).ready(function() {
$().mousemove(function(e){
$('#XY').html("Gbin1 X Axis : " + e.pageX + " | Gbin1 Y Axis " + e.pageY);
});
});

 

44. 使得整个列表元素(LI)可点击

$("ul li").click(function(){
window.location=$(this).find("a").attr("href"); return false;
});
<UL>
<LI><A href="#">GBin1 Link 1</A></LI>
<LI><A href="#">GBin1 Link 2</A></LI>
<LI><A href="#">GBin1 Link 3</A></LI>
<LI><A href="#">GBin1 Link 4</A></LI>
</UL> 

 

45. 使用jQuery来解析XML

function parseXml(xml) {
//find every Tutorial and print the author
$(xml).find("Tutorial").each(function()
{
$("#output").append($(this).attr("author") + "");
});
}

 

46. 判断一个图片是否加载完全

$('#theGBin1Image').attr('src', 'image.jpg').load(function() {
alert('This Image Has Been Loaded');
});

 

47. 使用jQuery命名事件

//Events can be namespaced like this
$('input').bind('blur.validation', function(e){
// ...
});
//The data method also accept namespaces
$('input').data('validation.isValid', true);

 

48. 判断cookie是否激活或者关闭

var dt = new Date();
dt.setSeconds(dt.getSeconds() + 60);
document.cookie = "cookietest=1; expires=" + dt.toGMTString();
var cookiesEnabled = document.cookie.indexOf("cookietest=") != -1;
if(!cookiesEnabled)
{
//cookies have not been enabled
}

 

49. 强制过期cookie

var date = new Date();
date.setTime(date.getTime() + (x * 60 * 1000));
$.cookie('example', 'foo', { expires: date });

 

50. 使用一个可点击的链接替换页面中所有URL

$.fn.replaceUrl = function() {
var regexp = /((ftp|http|https)://(w+:{0,1}w*@)?(S+)(:[0-9]+)?(/|/([w#!:.?+=&%@!-/]))?)/gi;
this.each(function() {
$(this).html(
$(this).html().replace(regexp,'<A href="$1">$1</A>')
);
});
return $(this);
}
//usage
$('#GBin1div').replaceUrl();