I am using magento 1.9, I have created mobile theme successfully and apply it to mobile device working fine but it is not working on web browser resize.
How can I apply this theme to browser resize.
If you are using a responsive design, then it should look at the width of the browser window and render a mobile, tablet or desktop view based on browser width.
However, it sounds like you've created a mobile-only theme for your Magento 1.9 site. A mobile-only theme can have some advantages, as it's usually very stripped down design and images and can make for a faster page load time. Plus, you don't have to rebuild the entire site with a responsive theme.
But note: a mobile design will not detect browser width changes.
In this case (using a mobile design), you'll want to have the site use the device type (i.e. iOS) to render the mobile site.
You'll do this in the System --> Configuration --> General --> Design --> Themes section:
I hope this helps!
It sounds like you want to change the theme on a browser resize, I don't think this is possible as you would need to refresh the page to reload all the theme's templates/dynamic code.
Based off your comment it sounds like your theme isn't responsive.
To make a theme responsive you need to build it that way, if your theme isn't responsive you will need to rebuild it.
If your theme is responsive then there isn't anything Magento needs to do, the CSS/JS from the theme will handle it.
To load a different theme for mobile you need to login to the admin and navigate to
system > config > design and add the user agents of the devices you want to change theme for. For example this will target mobile user-agents and change the theme if they match my expression.
The expressions used here are:
iPad|Silk|Kindle|Xoom|SCH-I800|GT-P5210|Android Tablet|Tablet|SM-T520|hudl|HT7S3|ME173X|JSS15Q|Nexus 7|Nexus 8|Nexus 9|Nexus 10
iPhone|iPod|BlackBerry|BB10|Pre|Palm|Googlebot-Mobile|mobi|Safari Mobile|Windows Mobile|Android|Opera Mini|mobile
Note that this won't change the theme on resize as it's based off user agent and not browser width. I don't think it's possible to change the whole theme on resize as it will need to fully reload templates/PHP/JS/CSS etc.