26 个 JQuery 使用小技巧(jQuery tips, tricks & solutions)

● 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();
});