给jquery对象添加自定义方法和扩展jquery类

原文地址：http://blog.sina.com.cn/s/blog_944b24ef0101epr5.html

一、给jQuery对象添加自定义方法

    方法一、$.fn. xxx

 

    方法二、jQuery.fn.extend({

         xxx:function(){

            alert($(this).val());

        }

    });

    方法一示例：

    $.fn.setCursorPosition =  function(position){
             if( this.lengh ==  0)  return this;
             return $( this).setSelection(position, position);
    }
       
    $.fn.setSelection =  function(selectionStart, selectionEnd) {
             if( this.lengh ==  0)  return this;
            input =  this[ 0];
       
             if (input.createTextRange) {
                     var range = input.createTextRange();
                    range.collapse( true);
                    range.moveEnd( 'character', selectionEnd);
                    range.moveStart( 'character', selectionStart);
                    range. select();
            }  else if (input.setSelectionRange) {
                    input. focus();
                    input.setSelectionRange(selectionStart, selectionEnd);
            }
       
             return this;
    }
       
    $.fn.focusEnd =  function(){
             this.setCursorPosition( this.val(). length);
    }

    

    方法二示例：

    $.fn.extend({
            setCursorPosition: function(position){
                     if( this.lengh ==  0)  return this;
                     return $( this).setSelection(position, position);
            },
            setSelection: function(selectionStart, selectionEnd) {
                     if( this.lengh ==  0)  return this;
                    input =  this[ 0];
               
                     if (input.createTextRange) {
                             var range = input.createTextRange();
                            range.collapse( true);
                            range.moveEnd( 'character', selectionEnd);
                            range.moveStart( 'character', selectionStart);
                            range. select();
                    }  else if (input.setSelectionRange) {
                            input. focus();
                            input.setSelectionRange(selectionStart, selectionEnd);
                    }
               
                     return this;
            },
            focusEnd: function(){
                     this.setCursorPosition( this.val(). length);
            }
    });

   

    以上定义都可如此调用：

    $( '.num'). click( function(){
            $( '.num').focusEnd();

    });

   

二、扩展jQuery类本身  为类添加新的方法

     方法一、jQuery.extend(object);

     方法二、jQuery. xxx=function(){};

    

    方法一示例：

    $.extend({
        add: function(a,b){ return a+b;},
        a: '2 chi gege '
    });
     alert($.add( 3, 4));  //7
     alert($.a);  //2 chi gege

    方法二示例：

    $.add2 =  function(a,b){
             return a-b;
    }
     alert($.add2( 4, 3));  //1