How to test UIWebView's 10MB limit on JavaScript?

How to test UIWebView's 10MB limit on JavaScript?

I'm trying to test UIWebView's 10MB limit on Javascript memory allocation.
Here is my code so far which I'm running on the simulator (iOS 5.1).
int size = 10485760+1024000*10;
int i = 13;
char *cStr = (char *) malloc(size); // 20MB buffer
char *lcStr = cStr;
lcStr+=i;
strcpy(cStr, "window._x = \'");
for ( ; i < size-4; i++){
if(i%2){
*lcStr = ' ';
}else{
*lcStr = 'c';
}
lcStr++;
}
strcpy(lcStr, "c\';\0");
NSString *longStr = [NSString stringWithCString:cStr
encoding:NSASCIIStringEncoding];
// by now 40MB used
//memory usage spikes to 60MB
NSString *result = [self.webView stringByEvaluatingJavaScriptFromString:
longStr];
free(cStr);
HTML/JS:
<script type="text/javascript">
setTimeout(function(){document.getElementById("one").innerText =
window._x;},3000);
</script>
My problem is that the code above doesn't result in any exception being
thrown by the UIWebView even though clearly the JS allocation at one point
is greater than 10MB. I've used instruments to verify the memory usage.
The end result of the entire program is that I see bunch of 'c ' are
printed on the screen in a webview but no crash.
Am I doing something wrong? How can I test this JS limit?