Jquery常用技巧收集整理(1)

jQuery 1.4给开发者带来了很多值得兴奋的新特性，同时使用jQuery的人也越来越多，为了方便大家对jQuery的使用，下面列出了一些jQuery使用技巧。比如有禁止右键点击、隐藏搜索文本框文字、在新窗口中打开链接、检测浏览器、预加载图片等等。具体如下：

禁止右键点击

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

隐藏搜索文本框文字

$(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); }
});
}

在新窗口中打开链接

$(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>

检测浏览器

注: 在版本jQuery 1.4中，$.support 替换掉了$.browser 变量。

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

预加载图片

$(document).ready(function() {

  jQuery.preloadImages = function()
  {
     for(var i = 0; i").attr("src", arguments[i]);

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

页面样式切换

$(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 href="default.css" type=text/css rel=stylesheet>
// the links
<A class=Styleswitcher href="#" rel=default.css>Default Theme</A>
<A class=Styleswitcher href="#" rel=red.css>Red Theme</A>
<A class=Styleswitcher href="#" rel=blue.css>Blue Theme</A>
});

列高度相同

如果使用了两个CSS列，使用此种方式可以是两列的高度相同。

$(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"));

  });

});

动态控制页面字体大小

$(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;
  });
});

返回页面顶部功能

$(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>
});

获得鼠标指针XY值

   $(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>
});

验证元素是否为空

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

替换元素

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

jQuery延时加载功能

$(document).ready(function() {

    window.setTimeout(function() {

    // do something

     }, 1000);

});

移除单词功能

$(document).ready(function() {

   var el = $('#id');

   el.html(el.html().replace(/word/ig, ""));

});

验证元素是否存在于jQuery对象集合中

$(document).ready(function() {

   if ($('#id').length) {

   // do something

}
});

使整个DIV可点击

$(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>
});

ID与Class之间转换当改变Window大小时，在ID与Class之间切换

$(document).ready(function() {

   function checkWindowSize() {
   if ( $(window).width() > 1200 ) {

     $('body').addClass('large');

   }
   else {

      $('body').removeClass('large');

        }

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

克隆对象

$(document).ready(function() {

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

  // how to use

<DIV idid=id></DIV>
});

使元素居屏幕中间位置

$(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();

});

写自己的选择器

$(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');

  });

});

统计元素个数

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

使用自己的Bullets

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

});

引用Google主机上的jQuery类库

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

禁用jQuery（动画）效果

$(document).ready(function() {

   jQuery.fx.off = true;

});

与其他JavaScript类库冲突解决方案

$(document).ready(function() {

  var $jq = jQuery.noConflict();

  $jq('#id').show();

});