Keypad toggles when website is visited in chrome browser on ipad

I have developed a website and used select2 jquery pluggin for the drop down. on the normal web page it is working fine. but when I visit the same site on mobile device (especially ipad with chrome browser) then selecting the drop-down values toggles keypad. it look like keyboard opens up and then closes then again opens up. this is happening too fast but it is not looking good.

I am unable to find the reason for same. what could be the possible reason for this.