Open HTML minifier
Open build.html
Copy all its code
In the HTML minfier's first textarea, paste the code you copied from build.html
Click Minify button
In the second textarea, minified code will appear. Copy that
Create a build.min.html
file and paste all your copied code in it
Open JSCompress
Select 2nd tab i.e. Upload JavaScript Files
Click on Choose Files
Select build.js
file
Click on Compress button
Download the file as build.js
in the same directory as of build.min.html