JS中的if else语句、多分支语句、嵌套语句的用法
<p>if语句的分类：</p><p>1、if else<br>
代码示例：</p>
<div class="codecolorer-container javascript vibrant" style="overflow:auto;white-space:nowrap;width:700px;"><table cellspacing="0" cellpadding="0"><tbody><tr><td class="line-numbers"><div>1<br>2<br>3<br>4<br>5<br>6<br>7<br></div></td><td><div class="javascript codecolorer"><span class="kw1">var</span> score<span class="sy0">=</span><span class="nu0">65</span><span class="sy0">;</span> <br>
<span class="kw1">var</span> daily<span class="sy0">=</span><span class="nu0">70</span><span class="sy0">;</span> <br>
<span class="kw1">if</span> <span class="br0">(</span>score<span class="sy0">></span><span class="nu0">60</span> <span class="sy0">&&</span>daily<span class="sy0">></span><span class="nu0">60</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"顺利毕业"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"很抱歉，没有顺利毕业！"</span><span class="br0">)</span> <br>
<span class="br0">}</span></div></td></tr></tbody></table></div>
<p>2、if else if else else<br>
代码示例：</p>
<div class="codecolorer-container javascript vibrant" style="overflow:auto;white-space:nowrap;width:700px;"><table cellspacing="0" cellpadding="0"><tbody><tr><td class="line-numbers"><div>1<br>2<br>3<br>4<br>5<br>6<br>7<br>8<br>9<br>10<br>11<br></div></td><td><div class="javascript codecolorer"><span class="sy0">/!*</span>多分支的<span class="kw1">if</span>判断：如果有符合条件的分支，之后的分支就不再执行<span class="sy0">*!/</span> <br>
<span class="kw1">var</span> score<span class="sy0">=</span><span class="nu0">65</span><span class="sy0">;</span> <br>
<span class="kw1">if</span> <span class="br0">(</span>score<span class="sy0"><</span><span class="nu0">60</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"不及格"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span>score<span class="sy0">>=</span><span class="nu0">60</span> <span class="sy0">&&</span> score<span class="sy0"><</span><span class="nu0">70</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"及格"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span>score <span class="sy0">>=</span><span class="nu0">70</span> <span class="sy0">&&</span> score<span class="sy0"><</span><span class="nu0">80</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"良"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span> <span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"优秀"</span><span class="br0">)</span> <br>
<span class="br0">}</span></div></td></tr></tbody></table></div>
<p>3、嵌套if<br>
代码示例：</p>
<div class="codecolorer-container javascript vibrant" style="overflow:auto;white-space:nowrap;width:700px;"><table cellspacing="0" cellpadding="0"><tbody><tr><td class="line-numbers"><div>1<br>2<br>3<br>4<br>5<br>6<br>7<br>8<br>9<br>10<br>11<br>12<br>13<br></div></td><td><div class="javascript codecolorer"><span class="kw1">var</span> score<span class="sy0">=</span><span class="nu0">65</span><span class="sy0">;</span> <br>
<span class="kw1">var</span> daily<span class="sy0">=</span><span class="nu0">70</span><span class="sy0">;</span> <br>
<span class="kw1">if</span> <span class="br0">(</span>score<span class="sy0">></span><span class="nu0">60</span> <span class="sy0">&&</span>daily<span class="sy0">></span><span class="nu0">60</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"顺利毕业"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span><span class="br0">{</span> <br>
<span class="kw1">if</span> <span class="br0">(</span>score <span class="sy0"><</span><span class="nu0">60</span> <span class="sy0">&&</span> daily<span class="sy0"><</span><span class="nu0">60</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"成绩和考勤不合格，无法毕业"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span>daily<span class="sy0"><</span><span class="nu0">60</span><span class="br0">)</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"考勤不合格，无法毕业"</span><span class="br0">)</span> <br>
<span class="br0">}</span><span class="kw1">else</span><span class="br0">{</span> <br>
alert<span class="br0">(</span><span class="st0">"成绩不合格，无法毕业"</span><span class="br0">)</span> <br>
<span class="br0">}</span> <br>
<span class="br0">}</span></div></td></tr></tbody></table></div>
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