输入框中获取当前光标位置&设置光标位置

function getCursorPos(ctrl){
  var pos = 0;
  if(document.selection){        //IE
    var range = document.selection.createRange();
    range.moveStart(‘character‘,-ctrl.value.length);
    pos = range.text.length;
  }else if(ctrl.selectionStart || ctrl.selectionStart == ‘0‘){//firefox
    pos = ctrl.selectionStart;
  }
  return pos;
}

function setCursorPos(ctrl,pos){
  if(ctrl.createTextRange){//IE
    var range = ctrl.createTextRange();
    range.collapse(true);
    range.moveStart(‘character‘,pos);
    range.moveEnd(‘character‘,pos);
    range.select();
  }else if(ctrl.setSelectionRange){//FF
    ctrl.focus();
    ctrl.setSelectionRange(pos,pos);
  } 
}