循环1929-2049判断二月份有28天的年份有多少个，输出计算结果。
<span class="hljs-built_in">let</span> cnt = <span class="hljs-number">0</span>
<span class="hljs-built_in">var</span> arr=[];
<span class="hljs-keyword">for</span>(<span class="hljs-built_in">var</span> i=<span class="hljs-number">1929</span>; i<=<span class="hljs-number">2049</span>; i++){
<span class="hljs-keyword">if</span>(i%<span class="hljs-number">4</span>==<span class="hljs-number">0</span> && i%<span class="hljs-number">100</span>!=<span class="hljs-number">0</span> || i%<span class="hljs-number">400</span>==<span class="hljs-number">0</span>){
arr.<span class="hljs-built_in">push</span>(i);
cnt++;
}
}
consloe.<span class="hljs-built_in">log</span>(cnt)
console.<span class="hljs-built_in">log</span>(arr)
<span class="hljs-keyword">let</span><span class="hljs-built_in"> count</span> = <span class="hljs-number">0</span>
<span class="hljs-keyword">for</span>(<span class="hljs-keyword">let</span> i = <span class="hljs-number">1929</span>; i <= <span class="hljs-number">2049</span>; i++;){
<span class="hljs-keyword">if</span>((i % <span class="hljs-number">4</span> == <span class="hljs-number">0</span> && i % <span class="hljs-number">100</span> != <span class="hljs-number">0</span>) || i % <span class="hljs-number">400</span>){
}<span class="hljs-keyword">else</span>{
<span class="hljs-built_in"> count</span>++
}
}
consloe.log<span class="hljs-built_in">(count</span>)
<span class="hljs-attribute">for</span>(var r=[],i=<span class="hljs-number">1929</span>;i<=<span class="hljs-number">2049</span>;i++){if (i%<span class="hljs-number">4</span>==<span class="hljs-number">0</span> && i%<span class="hljs-number">100</span>!=<span class="hljs-number">0</span> || i%<span class="hljs-number">400</span>==<span class="hljs-number">0</span>){r.push(i)}};console.log(r.length,r)