textarea中的光标位置

 var getCarePos = function (node) {
    var range, range2, pos = [];
    if (document.selection) {
      range = document.selection.createRange();
      range2 = range.duplicate();
      range2.moveToElementText(node);
      range2.setEndPoint('EndToEnd', range);
      pos = [range2.text.length - range.text.length, range2.text.length];
    } else {
      pos = [node.selectionStart, node.selectionEnd];
    }
    return pos;
 },

 setCarePos = function (node, pos) {
   var range;
   if (node.setSelectionRange) {
     node.setSelectionRange(pos, pos);
   } else if (node.createTextRange) {
     range = node.createTextRange();
     range.move('character', pos);
     range.select();
   }
     
 };