For example,
<script type="text/javascript" charset="utf-8" src="js/TechForm.js"></script>
using charset="utf-8" in <script> will force the script to output string in specified encoding.
As there some lines such as:
                el.value = "重签";
in the TechForm.js. Without the charset="utf-8", the value of el will not be displayed correctly.  And the specified "utf-8" will be the file encoding when you save the *.js file.