How to get the west panel width of inner layout

[chiefer]

How to get the west panel width of inner layout when I draged the split bar, or how can I get the drag event of the the split bar?

I used jQuery EasyUI 1.3.2

[stworthy]

Get the specified region panel first and then call 'options' method to get the panel's width.

Code:

var p = $('body').layout('panel','west');  // get the west panel
console.log(p.panel('options').width);  // output the panel's width
console.log(p.width());  // output the panel's inner width

[chiefer]

Thank you for your anwer.
Sorry, I didn't say clearly what I mean. I need to capture the width of the west panel when I drag the split bar every time.So, the key of the question is how to get the drag event of the the split bar.