Custom Code field mask error / cut data

Hello, the current plugin version masks manually inserted java script code in a wrong way in the field “Custom Code”.
If I inserted eg

alert("something");

after clicking the update button, the code shows:

alert(\"something\");

after the next update click:

alert(\\"something\\");

So on each click the mask characters will be extended, so the plugin creates syntax errors. The next problem is, that the text field cuts the code, so a long code line is stored correct, but I can not edit it again. Please use a textarea for adding manually code.
Thanks

http://ww.wp.xz.cn/extend/plugins/google-analytics-for-wordpress/