Q:

How to remove round corners in jQuery Mobile? 

How to remove the round edges (border-radius) from the particular element or from div tag that is using jQuery Mobile?

A:

Talking about buttons, you can apply following option to a button.
data-corners="false"

A code goes like this:
<a href="#" data-role="button" data-corners="false">push me</a>

The document is here:
http://jquerymobile.com/demos/1.2.0/docs/buttons/buttons-options.html
Thanks.

A:

In the jQuery mobile CSS file linked here, search for this string:
.ui-corner-tr {
I don't know if you're even using the default styles, but there's what I found based on the info you provided.
You should be able to change all four corners in that area (as .ui-corner-tr, .ui-corner-tl, .ui-corner-br, .ui-corner-bl, etc., etc.)

A:

In your css file (any) :
.ui-corner-all {
   -webkit-border-radius:.0 !important;
   border-radius: 0 !important;
}

