Tests which characters can be used before a protocol relative URL within an HTML style attribute.
<div id=x style="background:url($[chr]//fuzz.shazzer.co.uk/$[rand]?$[i]#)">test</div>
<div id=x style="background:url(0x09//fuzz.shazzer.co.uk/f6gyf7mdog?9#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/bb4e0o47n44?10#)">test</div>
<div id=x style="background:url(0x0C//fuzz.shazzer.co.uk/fs9awciress?12#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/k4f7n976qji?13#)">test</div>
<div id=x style="background:url( //fuzz.shazzer.co.uk/zvmttghq6q?32#)">test</div>
<div id=x style="background:url('//fuzz.shazzer.co.uk/o4szbtuvf9n?39#)">test</div>
<div id=x style="background:url(///fuzz.shazzer.co.uk/wpr2i0idyeq?47#)">test</div>
<div id=x style="background:url(\//fuzz.shazzer.co.uk/xf9o6s4o7jd?92#)">test</div>
<div id=x style="background:url(0x09//fuzz.shazzer.co.uk/8v5qyx9jor6?9#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/ryhsu5g2719?10#)">test</div>
<div id=x style="background:url(0x0C//fuzz.shazzer.co.uk/yx76hh0gsvk?12#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/43yv48fqif7?13#)">test</div>
<div id=x style="background:url( //fuzz.shazzer.co.uk/j5s85uaveef?32#)">test</div>
<div id=x style="background:url('//fuzz.shazzer.co.uk/of2stfcp9oh?39#)">test</div>
<div id=x style="background:url(///fuzz.shazzer.co.uk/lp6y8pg4qrj?47#)">test</div>
<div id=x style="background:url(\//fuzz.shazzer.co.uk/z65vjpqqlc?92#)">test</div>
<div id=x style="background:url(0x09//fuzz.shazzer.co.uk/9ye7pf2ut7v?9#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/449u9f202q2?10#)">test</div>
<div id=x style="background:url(0x0C//fuzz.shazzer.co.uk/w0y18j3qg4?12#)">test</div>
<div id=x style="background:url(
//fuzz.shazzer.co.uk/kygxbbxveg?13#)">test</div>