In Jenkins 1.480.3 we can no longer send HTML or XML formated texts using JavaScript Proxy. It works in 1.466 and for HTML and partly in 1.480.1.

function broken()
{
var promote = <st:bind value="${it}"/>
document.getElementById('result').innerHTML="";
promote.doStuff(function(t)

)
}
In this case the function(t) code will not be executed if the method returns code with HTML or XML tags.

I made a small example plugin https://github.com/hanabishi/js-breaker