26个Jquery使用小技巧

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、页面样式切换、所有列等高、动态控制页面字体大小、获得鼠标指针的X值Y值、验证元素是否为空、替换元素、延迟加载、验证元素是否存在于Jquery集合中、使DIV可点击、克隆对象、使元素居中、计算元素个数、使用Google主机上的Jquery类库、禁用Jquery效果、解决Jquery类库与其他Javascript类库冲突问题。

1. 禁止右键点击

1
2
3
4
5
$(document).ready( function (){
    $(document).bind( "contextmenu" , function (e){
        return false ;
    });
});

2. 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)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
$(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. 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.

1
2
3
4
5
6
7
8
9
10
11
$(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

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

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
$(document).ready( function () {
// Target Firefox 2 and above
if ($.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

This piece of code will prevent the loading of all images, which can be useful if you have a site with lots of images.

1
2
3
4
5
6
7
8
9
$(document).ready( function () {
jQuery.preloadImages = function ()
{
  for ( var i = 0; i<ARGUMENTS.LENGTH; jQuery(?<img { i++)> ").attr(" src ", arguments[i]);
  }
}
// how to use
$.preloadImages(" image1.jpg");
});

6. 页面样式切换

1
2
3
4
5
6
7
8
9
10
11
12
13
$(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 type=text/css href= "default.css" >
// 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>
});

7. 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。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
$(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. 动态控制页面字体大小

用户可以改变页面字体大小

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
$(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. 返回页面顶部功能

For a smooth(animated) ride back to the top(or any location).

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
$(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. 获得鼠标指针ＸＹ值

Want to know where your mouse cursor is?

1
2
3
4
5
6
7
8
9
$(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

This will allow you to check if an element is empty.

1
2
3
4
5
$(document).ready( function () {
  if ($( '#id' ).html()) {
   // do something
   }
});

13. 替换元素

Want to replace a div, or something else?

1
2
3
4
5
6
$(document).ready( function () {
   $( '#id' ).replaceWith( '
<DIV>I have been replaced</DIV>

' );
});

14. jQuery延时加载功能

Want to delay something?

1
2
3
4
5
$(document).ready( function () {
   window.setTimeout( function () {
     // do something
   }, 1000);
});

15. 移除单词功能

Want to remove a certain word(s)?

1
2
3
4
$(document).ready( function () {
   var el = $( '#id' );
   el.html(el.html().replace(/word/ig, "" ));
});

16. 验证元素是否存在于jquery对象集合中

Simply test with the .length property if the element exists.

1
2
3
4
5
$(document).ready( function () {
   if ($( '#id' ).length) {
  // do something
  }
});

17. 使整个DIV可点击

Want to make the complete div clickable?

1
2
3
4
5
6
7
8
9
$(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与Class之间转换.

当改变Window大小时，在ID与Class之间切换

1
2
3
4
5
6
7
8
9
10
11
$(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 div or an other element.

1
2
3
4
5
6
$(document).ready( function () {
   var cloned = $( '#id' ).clone();
// how to use
<DIV id=id></DIV>

});

20. 使元素居屏幕中间位置

Center an element in the center of your screen.

1
2
3
4
5
6
7
8
9
$(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. 写自己的选择器

Write your own selectors.

1
2
3
4
5
6
7
8
9
10
11
$(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 an element.

1
2
3
$(document).ready( function () {
   $( "p" ).size();
});

23. 使用自己的 Bullets

Want to use your own bullets instead of using the standard or images bullets?

1
2
3
4
5
6
$(document).ready( function () {
   $( "ul" ).addClass( "Replaced" );
   $( "ul > li" ).prepend( "‒ " );
 // how to use
 ul.Replaced { list-style : none; }
});

24. 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.

1
2
3
4
5
6
7
8
9
10
11
//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 type=text/javascript src= "http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js" ></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）效果

Disable all jQuery effects

1
2
3
$(document).ready( function () {
    jQuery.fx.off = true ;
});

26. 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.

1
2
3
4
$(document).ready( function () {
   var $jq = jQuery.noConflict();
   $jq( '#id' ).show();
});

英文原文：26-cool-and-usefull-jquery-tips-tricks-solutions