Here, I will explain how to minify the java script file and the CSS file.
Step 1: Go to this link:
Step 2: Copy your Javascrit code and CSS code from your file and paste it in this site Code Textbox and follow this site.
Step 3: Download the Minify .js file and replace your original js file with the minify js file.
Advantage
It saves the loading time of an application and also saves the bandwidth.