26 个 jQuery使用技巧

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.

1. 禁用右键点击（Disable right-click）

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

2. 禁用搜索文本框（Disappearing search field text）

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

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

3. 新窗口打开链接（Opening links in a new window）

$(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>

4. 检测浏览器（Detect browser）

$(document).ready(function() {
// Target Firefox 2 and above
if ($.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
}
});

5. 预加载图片（Preloading images）

$(document).ready(function() {
jQuery.preloadImages = function()
{
  for(var i = 0; i<arguments.length; i++)="" {="" jquery("<img="">").attr("src", arguments[i]);
  }
}
// how to use
$.preloadImages("image1.jpg");
});
</arguments.length;>

6. 样式筛选（CSS Style switcher）

$(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>
});

7. 列高度相同（Columns of equal 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"));
});
});

8. 字体大小调整（Font resizing）

$(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;
  });
});

9. 返回页面顶部（Smooth(animated) page scroll）

$(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>
});

11. 获取鼠标的xy坐标（Get the mouse cursor x and y axis）

$(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>

});

12. 验证元素是否为空（Verify if an Element is empty）

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

13. 替换元素（Replace a element）

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

');
});

14. 延迟加载（jQuery timer callback functions）

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

15. 移除单词（Remove a word）

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

16. 验证元素是否存在（Verify that an element exists in jQuery）

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

17. 使整个DIV可点击（Make the entire 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>

});

18. id和class切换（Switch between classes or id’s when resizing the window）

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

19. 克隆对象（Clone a object）

$(document).ready(function() {
   var cloned = $('#id').clone();
// how to use
<div id="id"></div>

});

20. 使元素居中屏幕（Center an element on the 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();
});

21. 自定义选择器（Write our own selector）

$(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');
  });
});

22. 统计元素个数（Count a element）

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

23. 自定义Bullets（Use Your Own Bullets）

$(document).ready(function() {
   $("ul").addClass("Replaced");
   $("ul > li").prepend("‒ ");
 // how to use
 ul.Replaced { list-style : none; }
});

24. 引用google分发的jQuery（Let Google host jQuery for you）

//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><script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" type="text/javascript"></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>

25. 禁用jQuery动画（Disable jQuery animations）

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

26. 防止不兼容冲突（No conflict-mode）

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

jquery 速查表：

参考推荐：
jQuery
jQuery UI
14 days of jQuery
Learning jQuery
Cheatsheet jQuery 1.1.3
Improve your jQuery – 25 excellent tips