Using JS to implement a simple calculator

Use JS to complete a simple calculator for your reference. The specific contents are as follows

Requirements: The input value can only be a number, use a regular expression
onchange(): Executes an event when the value changes
onblur(): Executes an event when the mouse moves out

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Calculator</title>
</head>
<body>
    <div style="text-align: center;">
        <input type="text" id="1" onkeyup="this.value=this.value.replace(/[^\d]/g,'') " >
    <select name="select" id="select">
        <option value="null">Please select</option>
        <option value="0">+</option>
        <option value="1">-</option>
        <option value="2">*</option>
        <option value="3">/</option>
    </select>
    <input type="text" id="2" onkeyup="this.value=this.value.replace(/[^\d]/g,'') ">
    =
    <input type="text" id="3" onkeyup="this.value=this.value.replace(/[^\d]/g,'') "><br><br>
    </div>
    <div style="text-align: center;">
        <input type="button" id="button"value="calculate">
    </div>
    <script>
        
    function accAdd(arg1,arg2){ 
        var r1,r2,m; 
        try{
            r1=arg1.toString().split(".")[1].length
        }catch(e){
            r1=0
        } 
        try{
            r2=arg2.toString().split(".")[1].length
        }catch(e){
            r2=0
        } 
        m=Math.pow(10,Math.max(r1,r2)) 
        return (arg1*m+arg2*m)/m 
        } 
        Number.prototype.add = function (arg) { 
        return accAdd(arg,this); 
        }


    function Subtr(arg1,arg2){
        var r1,r2,m,n;
 
        try{
            r1=arg1.toString().split(".")[1].length
        }catch(e){
            r1=0
        }
 
        try{
            r2=arg2.toString().split(".")[1].length
        }catch(e){
            r2=0
        }
        m=Math.pow(10,Math.max(r1,r2));
 
     // last modified by deeka
     // Dynamically control the precision length n=(r1>=r2)?r1:r2;
        return ((arg1*m-arg2*m)/m).toFixed(n);
    }
    function accMul(arg1,arg2) //multiplication { 
        var m=0,s1=arg1.toString(),s2=arg2.toString(); 
        try{
            m+=s1.split(".")[1].length
        }catch(e){} 
        try{
            m+=s2.split(".")[1].length
        }catch(e){} 
        return Number(s1.replace(".",""))*Number(s2.replace(".","")) / Math.pow(10,m) 
        } 
 
    //Add a mul method to the Number type to make it more convenient to call. 
    Number.prototype.mul = function (arg) { 
    return accMul(arg, this); 
    } 

    function accDiv(arg1,arg2){ 
    var t1=0,t2=0,r1,r2; 
    try{
        t1=arg1.toString().split(".")[1].length
    }catch(e){} 
    try{
        t2=arg2.toString().split(".")[1].length
    }catch(e){} 
     with(Math){ 
        r1=Number(arg1.toString().replace(".","")) 
        r2=Number(arg2.toString().replace(".","")) 
        return (r1/r2)*pow(10,t2-t1); 
        } 
    } 
        Number.prototype.div = function (arg) { 
        return accDiv(this, arg); 
    }


        document.getElementById('button').onclick=function(){
            var num1 = document.getElementById('1').value;
            var num2 = document.getElementById('2').value;
            var num3;
            var op = document.getElementById('select').value;
            switch(op){
                case '0':
                    num3 = accAdd(num1,num2);
                    break;
                case '1':
                    num3 = Subtr(num1,num2);
                    break;
                case '2':
                    num3=accMul(num1,num2);
                    break;
                case '3':
                    num3=accDiv(num1,num2);
                    break;
            }
            document.getElementById('3').value=num3;
        }
       
    </script>

</body>
</html>

Effect picture:

The above is the full content of this article. I hope it will be helpful for everyone’s study. I also hope that everyone will support 123WORDPRESS.COM.

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