如何实现由按钮控制文本滚动

一、比较保守的方法，如果要放到按钮上的效果就onRollOver,别忘了再写个onRollOut配它哦。

以下为引用的内容： upBtn.onPress = function() {               onEnterFrame = function () {                      textHolder.scroll += 2;               };        }; upBtn.onRelease = function() {               delete onEnterFrame;        }; dnBtn.onPress = function() {               onEnterFrame = function () {                      textHolder.scroll -= 2;               };        }; dnBtn.onRelease = function() {               delete onEnterFrame;        };

二、

以下为引用的内容： this.createEmptyMovieClip("a_mc", 100); this.createEmptyMovieClip("c_mc", 200); down_btn.onPress = function() {  a_mc.onEnterFrame = function() {   textField_txt.scroll += 1;  }; }; down_btn.onRollOver = function() {  a_mc.onEnterFrame = function() {   textField_txt.scroll += 3;  }; }; up_btn.onPress = function() {  c_mc.onEnterFrame = function() {   textField_txt.scroll -= 1;  }; }; up_btn.onRollOver = function() {  c_mc.onEnterFrame = function() {   textField_txt.scroll -= 3;  }; }; up_btn.onRelease = function() {  delete c_mc.onEnterFrame; }; up_btn.onRollOut = function() {  delete c_mc.onEnterFrame; }; down_btn.onRollOut = function() {  delete a_mc.onEnterFrame; }; down_btn.onRelease = function() {  delete a_mc.onEnterFrame; };