The images are very blurry in my game

cocos2d-x JavaScript
#1

I am using cocos2d-html 5 v 2.1.5. All images in my game are very blurry. Even if I adapt different sizes of resource (I prepared 8 sets of resources in different sizes) to different sizes of screen.

my original image:

the image shown in the game:

This is really frustrating! Who can help me? I would be very thankful!

The game images are blurred when I set viewport's width to device-width
#2

I remove the following setting viewport statement from index.html then the images show fine:

<meta name="viewport"  content="width=device-width,user-scalable=no,initial-scale=1.0"/>