js代码实现计算器-js教程-PHP中文网

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js代码实现计算器
Apr 21, 2018 am 10:31 AM
javascript 计算器
这篇文章介绍的内容是关于js代码实现计算器，有着一定的参考价值，现在分享给大家，有需要的朋友可以参考一下
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&lt;!DOCTYPE html&gt;  
&lt;html&gt;  
&lt;head&gt;  
&lt;meta charset=&quot;utf-8&quot;&gt;   
&lt;title&gt;&lt;/title&gt;   
&lt;script&gt;  
   
function myjs(){  
        
    var ft =  document.getElementById(&quot;fhv&quot;).value;  
    var v1 =  document.getElementById(&quot;v1&quot;).value;  
    var v2 =  document.getElementById(&quot;v2&quot;).value;  
     var v3 = &#39;&#39;;  
     //alert(ft);  
     //alert(v1);  
     //alert(v2);  
     //alert(v3);  
    if(&quot;+&quot; == ft){  
         v3 =  Number(v1) +Number(v2);  
    }else if(&quot;-&quot; == ft){  
         v3 = Number(v1)-Number(v2);  
    }else if(&quot;*&quot; == ft){  
         v3 = Number(v1)*Number(v2);  
    }else if(&quot;/&quot; == ft){  
         v3 = Number(v1)/Number(v2);  
    }else{  
        v3 = &#39;&#39;;   
    }  
     //alert(v3);  
    document.getElementById(&quot;v3&quot;).value=  v3;  
    document.getElementById(&quot;z3&quot;).innerHTML = v3;  
       
}  
function changeFh(){  
    var fu =  document.getElementById(&quot;fh&quot;);  
    var idx= fu.selectedIndex ;     
    var ft =  fu.options[idx].value;  
    var fs =  fu.options[idx].text;  
    //alert(ft == &quot;+&quot;);  
    if(&quot;+&quot; == ft){  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;加&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;+&#39;;  
    }else if(&quot;-&quot; == ft){  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;减&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;-&#39;;  
    }else if(&quot;*&quot; == ft){  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;乘&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;*&#39;;  
    }else if(&quot;/&quot; == ft){  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;除&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;/&#39;;  
    }else{  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;请选择符号&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;&#39;;  
    }  
    var v1 = document.getElementById(&quot;v1&quot;).value;  
    v1 = v1.replace(/\s+/g,&quot;&quot;);  
    
    if(v1.length == 0){  
        document.getElementById(&quot;fhz&quot;).innerHTML = &#39;&#39;;   
    }  
   
    }  
    function radow_load(){  
        changeFh();  
    }  
    function checkValue1(){  
        var v1 = document.getElementById(&quot;v1&quot;).value;  
        v1 = v1.replace(/\s+/g,&quot;&quot;);  
        //alert(isNaN(v1));  
        if(isNaN(v1)){  
            document.getElementById(&quot;v1&quot;).value = &quot;&quot;    ;  
            alert(&quot;请输入数字!&quot;);  
        }  
        document.getElementById(&quot;z1&quot;).innerHTML = v1;   
    }     
    function checkValue2(){  
        var v2 = document.getElementById(&quot;v2&quot;).value;  
        v2 = v2.replace(/\s+/g,&quot;&quot;);  
        if(isNaN(v2)){  
            document.getElementById(&quot;v2&quot;).value = &#39;&#39;;  
            alert(&quot;请输入数字&quot;);  
        }  
        var fhx = document.getElementById(&quot;fhv&quot;).value;  
        if(fhx.length == 0){  
            document.getElementById(&quot;v2&quot;).value = &#39;&#39;;  
            alert(&quot;请输入符号&quot;);  
            return;  
        }  
        document.getElementById(&quot;fhz&quot;).innerHTML = fhx;   
        document.getElementById(&quot;z2&quot;).innerHTML = v2;   
        document.getElementById(&quot;fhzy&quot;).innerHTML = &#39;=&#39;;   
    }     
    function clearValue(){  
        //alert(&quot;clear&quot;);  
        document.getElementById(&quot;v1&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;v2&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;v3&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;fhv&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;fh&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;fhz&quot;).value=  &#39;&#39;;  
        document.getElementById(&quot;an&quot;).innerHTML=  &#39;请选择符号&#39;;  
        document.getElementById(&quot;z1&quot;).innerHTML=  &#39;&#39;;  
        document.getElementById(&quot;z2&quot;).innerHTML=  &#39;&#39;;  
        document.getElementById(&quot;z3&quot;).innerHTML=  &#39;&#39;;  
        document.getElementById(&quot;fhzy&quot;).innerHTML=  &#39;&#39;;  
        document.getElementById(&quot;fhz&quot;).innerHTML=  &#39;&#39;;  
   
    }  
&lt;/script&gt;  
&lt;/head&gt;  
&lt;body onload=&quot;radow_load()&quot;&gt;  
       
&lt;h1&gt;我的 Web 页面&lt;/h1&gt;  
&lt;table&gt;  
&lt;tr&gt;  
&lt;td&gt;  
&lt;input id=&quot;v1&quot; name=&quot;第一个值&quot;   onchange=&quot;checkValue1()&quot;/&gt;  
&lt;select id=&quot;fh&quot; name=&quot;符号&quot; onchange=&quot;changeFh()&quot; &gt;  
    &lt;option value =&quot;+&quot;&gt;+&lt;/option&gt;  
    &lt;option value =&quot;-&quot;&gt;-&lt;/option&gt;  
    &lt;option value=&quot;*&quot;&gt;*&lt;/option&gt;  
    &lt;option value=&quot;/&quot;&gt;/&lt;/option&gt;  
&lt;/select&gt;  
&lt;input id=&quot;v2&quot;  name=&quot;第二个值&quot; onchange=&quot;checkValue2()&quot;/&gt;  
&lt;b&gt;=&lt;/b&gt;  
&lt;input id=&quot;v3&quot;  name=&quot;结果&quot;/&gt;  
 &lt;button id=&quot;an&quot; type=&quot;button&quot; onclick=&quot;myjs()&quot;&gt;请选择符号&lt;/button&gt;  
 &lt;button id=&quot;ca&quot; type=&quot;button&quot; onclick=&quot;clearValue()&quot;&gt;清空&lt;/button&gt;  
&lt;input id=&quot;fhv&quot;  name=&quot;fhv&quot; hidden=&quot;true&quot;/&gt;  
&lt;/td&gt;  
&lt;/tr&gt;  
&lt;tr&gt;  
&lt;td&gt;  
&lt;b id=&quot;z1&quot;&gt;&lt;/b&gt;  
&lt;b id=&quot;fhz&quot;&gt;&lt;/b&gt;  
&lt;b id=&quot;z2&quot;&gt;&lt;/b&gt;  
&lt;b id=&quot;fhzy&quot;&gt;&lt;/b&gt;  
&lt;b id=&quot;z3&quot;&gt;&lt;/b&gt;  
&lt;/td&gt;  
   
&lt;/tr&gt;  
   
&lt;/table&gt;  
&lt;/body&gt;  
&lt;/html&gt;