26个JQuery使用小技巧

http://www.opensourcehunter.com/2010/02/27/26-cool-and-usefull-jquery-tips-tricks-solutions/

 

The use of the jQuery library is growing and growing(just released jQuery 1.4 ), more and more people are using this useful javascript library. This means that more and more useful jQuery tips, tricks and solutions are coming available. That’s why i created a small list of 26 cool and useful jQuery tips, tricks and solutions.

        jQuery has a lot of very useful plugins   that can help you with almost anything, but there are a couple of plugins that aren’t that smart to use, why? Well sometimes 1 or 2 lines of jQuery code can do the same thing(or even better), so why use a big script if you can do the same trick with a small piece of code.

        As many of you already know, jQuery can do a lot of things in more than just one way, so if you see a tip, trick or solution and think/know this can be done better, smarter or faster please let me know, post and share it in a comment below of just email me this, so that i can use this for part 2.

● Disable right-click(禁止右键点击)
        Disable right-click contextual menu.

$(document).ready(
function
(){
  $(document).bind("contextmenu"
, 
function
(e) {
    return
 
false
;
  });
});

  ● Disappearing search field text(隐藏搜索文本框文字)
        Hide when clicked in the search field, the value.(example can be found below in the comment fields)

$(document).ready(
function
() {
  $("input.text1"
).val(
"Enter your search text here"
);
  textFill($('input.text1'
));
});

// input focus text function
function
 textFill(input) {
  var
 originalvalue = input.val();
  input.focus(function
() {
    if
( $.trim(input.val()) == originalvalue ) {
      input.val(''
);
    }
  });
  input.blur( function
() {
    if
( $.trim(input.val()) == 
''
 ) {
      input.val(originalvalue);
    }
  });
}

 

Opening links in a new window(在新窗口中打开链接)
        XHTML 1.0 Strict doesn’t allow this attribute in the code, so use this to keep the code valid.

$(document).ready(
function
() {
  //Example 1: Every link will open in a new window
  $('a[href^="http://"]'
).attr(
"target"
, 
"_blank"
);

  //Example 2: Links with the rel="external" attribute will only open in a new window
  $('a[@rel$='
external
']'
).click(
function
() {
    this
.target = 
"_blank"
;
  });
});
// how to use
<a href="http://www.opensourcehunter.com"
 rel=
"external"
>open link</a>

 

Detect browser(检测浏览器)
        Change/add something for a certain browser.
        Notice: As of jQuery 1.4, the $.browser variable is replaced by $.support.

$(document).ready(
function
() {
// Target Firefox 2 and above
if
 ($.browser.mozilla && $.browser.version >= 
"1.8"
 ){
    // do something
}

// Target Safari
if
( $.browser.safari ){
    // do something
}

// Target Chrome
if
( $.browser.chrome){
    // do something
}

// Target Camino
if
( $.browser.camino){
    // do something
}

// Target Opera
if
( $.browser.opera){
    // do something
}

// Target IE6 and below
if
 ($.browser.msie && $.browser.version <= 6 ){
    // do something
}

// Target anything above IE6
if
 ($.browser.msie && $.browser.version > 6){
    // do something
}
});

 

● Preloading images(预加载图片)
        This piece of code will prevent the loading of all images, which can be useful if you have a site with lots of images.

$(document).ready(
function
() {
  jQuery.preloadImages = function
() {
    for
(
var
 i = 0; i < arguments.length; i++) {
      $("<img>"
).attr(
"src"
, arguments[i]);
    }
  }

  // how to use
  $.preloadImages("image1.jpg"
);
});

 CSS Styleswitcher(页面样式切换)
        Switch between different styles?

$(document).ready(
function
() {
  $("a.Styleswitcher"
).click(
function
() {
    // swicth the LINK REL attribute with the value in A REL attribute
    $('link[rel=stylesheet]'
).attr(
'href'
 , $(
this
).attr(
'rel'
));
    });
});

// how to use
// place this in your header
<link rel="stylesheet"
 href=
"default.css"
 type=
"text/css"
>
// the links
<a href="#"
 
class
=
"Styleswitcher"
 rel=
"default.css"
>Default Theme</a>
<a href="#"
 
class
=
"Styleswitcher"
 rel=
"red.css"
>Red Theme</a>
<a href="#"
 
class
=
"Styleswitcher"
 rel=
"blue.css"
>Blue Theme</a>

 Columns of equal height(列高度相同)
        If you are using two CSS columns, use this to make them exactly the same height.

$(document).ready(
function
() {
  function
 equalHeight(group) {
    tallest = 0;
    group.each(function
() {
      thisHeight = $(this
).height();
      if
 (thisHeight > tallest) {
        tallest = thisHeight;
      }
    });
    group.height(tallest);
  }

  // how to use
  $(document).ready(function
() {
    equalHeight($(".left"
));
    equalHeight($(".right"
));
  });
});

 Font resizing(动态控制页面字体大小)
        Want to let the users change there font size?

$(document).ready(
function
() {
  // Reset the font size(back to default)
  var
 originalFontSize = $(
'html'
).css(
'font-size'
);
  $(".resetFont"
).click(
function
() {
    $('html'
).css(
'font-size'
, originalFontSize);
  });

  // Increase the font size(bigger font0
  $(".increaseFont"
).click(
function
() {
    var
 currentFontSize = $(
'html'
).css(
'font-size'
);
    var
 currentFontSizeNum = parseFloat(currentFontSize, 10);
    var
 newFontSize = currentFontSizeNum * 1.2;
    $('html'
).css(
'font-size'
, newFontSize);
    return
 
false
;
  });

  // Decrease the font size(smaller font)
  $(".decreaseFont"
).click(
function
() {
    var
 currentFontSize = $(
'html'
).css(
'font-size'
);
    var
 currentFontSizeNum = parseFloat(currentFontSize, 10);
    var
 newFontSize = currentFontSizeNum*0.8;
    $('html'
).css(
'font-size'
, newFontSize);
    return
 
false
;
  });
});

 

Smooth(animated) page scroll(返回页面顶部功能)
        For a smooth(animated) ride back to the top(or any location).

$(document).ready(
function
() {
  $('a[href*=#]'
).click(
function
() {
   if
 (location.pathname.replace(/^\
//,'') == this.pathname.replace(/^\//,'')
       && location.hostname == this
.hostname) {
     var
 $target = $(
this
.hash);
     $target = $target.length && $target || $('[name='
 + 
this
.hash.slice(1) +
']'
);
     if
 ($target.length) {
       var
 targetOffset = $target.offset().top;
       $('html,body'
).animate( { scrollTop: targetOffset }, 900);
       return
 
false
;
     }
   }
  });
});

// how to use
// place this where you want to scroll to
<a name="top"
></a>
// the link
<a href="#top"
>go to top</a>

 

Get the mouse cursor x and y axis(获得鼠标指针 X/Y 值)
        Want to know where your mouse cursor is?

$(document).ready(
function
() {
  $().mousemove(function
(e) {
    // display the x and y axis values inside the div with the id XY
    $('#XY'
).html(
"X Axis : "
 + e.pageX + 
" | Y Axis "
 + e.pageY);
  });
});

// how to use
<div id="XY"
></div>

 

Verify if an Element is empty(验证元素是否为空)
        This will allow you to check if an element is empty.

$(document).ready(
function
() {
  if
 ($(
'#id'
).html()) {
    // do something
  }
});

 

Replace a element(替换元素)
        Want to replace a div, or something else?

$(document).ready(
function
() {
  $('#id'
).replaceWith(
'<div>I have been replaced</div>'
);
});

 

jQuery timer callback functions(jQuery 延时加载功能)
        Want to delay something?

$(document).ready(
function
() {
  window.setTimeout(function
() {
    // do something
  }, 1000);
});

 Remove a word(移除单词功能)
        Want to remove a certain word(s)?

$(document).ready(
function
() {
  var
 el = $(
'#id'
);
  el.html(el.html().replace(/word/ig, ""
));
});

 

Verify that an element exists in jQuery(验证元素是否存在)
        Simply test with the .length property if the element exists.

$(document).ready(
function
() {
  if
 ($(
'#id'
).length) {
    // do something
  }
});

 

Make the entire DIV clickable(使整个 DIV 可点击)
        Want to make the complete div clickable?

$(document).ready(
function
() {
  $("div"
).click(
function
() {
    // get the url from href attribute and launch the url
    window.location = $(this
).find(
"a"
).attr(
"href"
);
    return
 
false
;
  });
});

// how to use
<div><a href="index.html"
>home</a></div>

 

● Switch between classes or id’s when resizing the window(id 与 class 之间转换)
        Want to switch between a class or id, when resizing the window?

$(document).ready(
function
() {
  function
 checkWindowSize() {
    if
 ( $(window).width() > 1200 ) {
      $('body'
).addClass(
'large'
);
    } else
 {
      $('body'
).removeClass(
'large'
);
    }
  }

  $(window).resize(checkWindowSize);
});

 ● Clone a object(克隆对象)
        Clone a div or an other element.

$(document).ready(
function
() {
  var
 cloned = $(
'#id'
).clone();
});

// how to use
<div id="id"
></div>

 

● Center an element on the screen(使元素居屏幕中间位置)
        Center an element in the center of your screen.

$(document).ready(
function
() {
  jQuery.fn.center = function
() {
    this
.css(
"position"
,
"absolute"
);
    this
.css(
"top"
, ( $(window).height() - 
this
.height() ) / 2+$(window).scrollTop() + 
"px"
);
    this
.css(
"left"
, ( $(window).width() - 
this
.width() ) / 2+$(window).scrollLeft() + 
"px"
);
    return
 
this
;
  }
  $("#id"
).center();
});

 ● Write our own selector(写自己的选择器)
        Write your own selectors.

$(document).ready(
function
() {
  $.extend($.expr[':'
], {
      moreThen1000px: function
(a) {
      return
 $(a).width() > 1000;
    }
  });

  $('.box:moreThen1000px'
).click(
function
() {
    // creating a simple js alert box
    alert('The element that you have clicked is over 1000 pixels wide'
);
  });
});

 

● Count a element(统计元素个数)
        Count an element.

$(document).ready(
function
() {
  $("p"
).size();
});

 

● Use Your Own Bullets(使用自己的 Bullets)
        Want to use your own bullets instead of using the standard or images bullets?

$(document).ready(
function
() {
  $("ul"
).addClass(
"Replaced"
);
  $("ul > li"
).prepend(
"- "
);
});

// how to use
ul.Replaced { list-style : none; }

 ● Let Google host jQuery for you(引用 Google 主机上的 jQuery 类库)
        Let Google host the jQuery script for you. This can be done in 2 ways.

// Example 1
<script src="http://www.google.com/jsapi"
></script>
<script type="text/javascript"
>
  google.load("jquery"
, 
"1.2.6"
);
  google.setOnLoadCallback(function
() {
    // do something
  });
</script>

 // Example 2:(the best and fastest way)
<script type="text/javascript"
 src=
"http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js"
></script>

 ● Disable jQuery animations(禁用 jQuery 动画效果)
        Disable all jQuery effects.

$(document).ready(
function
() {
  jQuery.fx.off = true
;
});

 ● No conflict-mode(与其他 Javascript 类库冲突解决方案)
        To avoid conflict other libraries on your website, you can use this jQuery Method, and assign a different variable name instead of the dollar sign。

$(document).ready(
function
() {
  var
 $jq = jQuery.noConflict();
  $jq('#id'
).show();
});