diff options
Diffstat (limited to 'files/zh-cn/web/javascript/reference/global_objects/math/sign')
| -rw-r--r-- | files/zh-cn/web/javascript/reference/global_objects/math/sign/index.html | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/files/zh-cn/web/javascript/reference/global_objects/math/sign/index.html b/files/zh-cn/web/javascript/reference/global_objects/math/sign/index.html index ca7678c9f0..9c41082511 100644 --- a/files/zh-cn/web/javascript/reference/global_objects/math/sign/index.html +++ b/files/zh-cn/web/javascript/reference/global_objects/math/sign/index.html @@ -50,12 +50,12 @@ Math.sign(); // NaN <h2 id="Compatibility" name="Compatibility">Polyfill</h2> -<pre class="brush: js language-js"><code class="language-js"><span class="keyword token">function</span> <span class="function token">sign<span class="punctuation token">(</span></span>x<span class="punctuation token">)</span> <span class="punctuation token">{</span> - x <span class="operator token">=</span> <span class="operator token">+</span>x<span class="comment token"> ;// convert to a number -</span> <span class="keyword token">if</span> <span class="punctuation token">(</span>x <span class="operator token">===</span> <span class="number token">0</span> <span class="operator token">||</span> <span class="function token">isNaN<span class="punctuation token">(</span></span>x<span class="punctuation token">)</span><span class="punctuation token">)</span> - <span class="keyword token">return</span> x; - <span class="keyword token">return</span> x <span class="operator token">></span> <span class="number token">0</span> <span class="operator token">?</span> <span class="number token">1</span> <span class="punctuation token">:</span> <span class="operator token">-</span><span class="number token">1;</span> -<span class="punctuation token">}</span></code></pre> +<pre class="brush: js language-js"><code class="language-js">function sign(x) { + x = +x ;// convert to a number + if (x === 0 || isNaN(x)) + return x; + return x > 0 ? 1 : -1; +}</code></pre> <p> </p> |