黑马程序员_js中去掉空格

//去掉字串左边的空格

function ltrim(str)

{   if (str.charat(0) == " ")

  {    

     //如果字串左边第一个字符为空格    

     str = str.slice(1);//将空格从字串中去掉     //这一句也可改成 str = str.substring(1, str.length);    

     str = ltrim(str);    //递归调用  

  }  

return str;

}

//去掉字串右边的空格

function rtrim(str)

{   var ilength;  

     ilength = str.length;  

    if (str.charat(ilength - 1) == " ")  

   {     //如果字串右边第一个字符为空格    

         str = str.slice(0, ilength - 1);//将空格从字串中去掉     //这一句也可改成 str = str.substring(0, ilength - 1);    

         str = rtrim(str);   

        //递归调用  

   }  

   return str;

}

   //去掉字串两边的空格

function trim(str)

{  

     return ltrim(rtrim(str));

}

//------------- function  alltrim(a_strvarcontent)

      {     var pos1, pos2,  newstring;      

             pos1 = 0;    

             pos2 = 0;  

             newstring = ""      

             if ( a_strvarcontent.length > 0 )    

            {         for( i=0; i<=a_strvarcontent.length; i++)     //recon: 这句应该有错误,应改成:     //for( i=0; i<a_strvarcontent.length; i++)                       {             if ( a_strvarcontent.charat(i) == " " )               

                                           pos1 = pos1 + 1;            

                                     else                 break;         

                      }                

                      for( i=a_strvarcontent.length; i>=0 ; i--)     //recon: 这句应该有错误,应改成:     //for( i=a_strvarcontent.length-1; i>=0 ; i--)                      {            

                                     if ( a_strvarcontent.charat(i) == " " )                

                                               pos2 = pos2 + 1;            

                                     else                 break;           

                     }                

                     newstring = a_strvarcontent.substring(pos1, a_strvarcontent.length-pos2)       

               }      

        return newstring;

}

//------------- function jtrim(sstr)

                  { 

                          var astr="";

                          var dstr="";

                          var flag=0;

                          for (i=0;i<sstr.length;i++)    

                          {

                                       if ((sstr.charat(i)!= )||(flag!=0))    

                                       {

                                                   dstr+=sstr.charat(i);     

                                                   flag=1;       

                                         }    

                           }

                           flag=0;

                           for (i=dstr.length-1;i>=0;i--)  

                          {

                                         if ((dstr.charat(i)!= )||(flag!=0))    

                                        {

                                                      astr+=dstr.charat(i);     

                                                      flag=1;        

                                         }    

                           }

                          dstr="";

                          for (i=astr.length-1;i>=0;i--)

                          {

                                    dstr+=astr.charat(i);

                                    return dstr;

                          }

 }

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posted @ 2012-12-01 15:42  liqing123  阅读(153)  评论(0编辑  收藏  举报