ccurrence of <code>x</code> in <code>this</code> Array, searching front to back.</p>
<p>If <code>x</code> is found by checking standard equality, the function returns its index.</p>
<p>If <code>x</code> is not found, the function returns -1.</p>
<p>If <code>fromIndex</code> is specified, it will be used as the starting index to search from,
otherwise search starts with zero index. If it is negative, it will be taken as the
offset from the end of <code>this</code> Array to compute the starting index. If give