webapp 中怎么点击按钮，复制文本内容

//点击复制  
            function copyToClip() {  
                var text= getId("text").innerHTML;  
                if(mui.os.android) {  
                    var Context = plus.android.importClass("android.content.Context");  
                    var main = plus.android.runtimeMainActivity();  
                    var clip = main.getSystemService(Context.CLIPBOARD_SERVICE);  
                    plus.android.invoke(clip, "setText", text);  
                } else {  
                    var UIPasteboard = plus.ios.importClass("UIPasteboard");  
                    var generalPasteboard = UIPasteboard.generalPasteboard();  
                    // 设置/获取文本内容:  
                    generalPasteboard.setValueforPasteboardType(text, "public.utf8-plain-text");  
                    var value = generalPasteboard.valueForPasteboardType("public.utf8-plain-text");  
                }  
                mui.toast("复制成功");  
            }