Mirrur

function locatePoint(oInputElem, start, end){ 
     if (oInputElem.setSelectionRange) { //FF
          setTimeout(function() { 
               oInputElem.setSelectionRange(start, end); //将光标定位在textarea的开头，需要定位到其他位置的请自行修改 
               oInputElem.focus(); 
          }, 0); 
     }else if (oInputElem.createTextRange) { //IE
          var tempText=oInputElem.createTextRange(); 
          tempText.moveStart("character",0-tempText.text.length+start);
          tempText.moveEnd("character",0-tempText.text.length+end); //结束点在容器起始位置,配合moveStart可以选中指定位置的字符
          tempText.select(); 
     } 
} 

 $('.auto input').click(function(){
      var o = document.getElementById("a");
      $('.auto input').val('年');
      locatePoint(o, 0, 0);
      //$('.auto input').focus();
      //document.getElementById("a").setSelectionRange(0,0);

 });

本文链接：javascript光标的定位