Untitled

<html>
<head> </head>

<body>
<button>Deepak calculator </button>
<br><br>
<input type="text"  name="abc" id="monitor"/>
<br>
<button onclick="one()" > 1 </button>
<button onclick="two()"> 2</button>
<button onclick="three()"> 3 </button>
<button onclick="four()"> 4 </button>
<br>
<button onclick="plus()"> + </button>
<button onclick="minus()"> -</button>
<button onclick="mul()"> *</button>
<button onclick="div()"> /</button>

<button onclick="calculate()"> = </button>

<script>
var a,b,result,snumber,plus,minus,mul,div,operator;
function one(){
 a=document.getElementById("monitor").value;
document.getElementById("monitor").value=a+"1";
}

function two(){
 a=document.getElementById("monitor").value;
document.getElementById("monitor").value=a+"2";
}

function three(){
 a=document.getElementById("monitor").value;
document.getElementById("monitor").value=a+"3";
}

function four(){
 a=document.getElementById("monitor").value;
document.getElementById("monitor").value=a+"4";
}

function plus(){
 operator="+";
 plus=parseFloat(document.getElementById("monitor").value);
 document.getElementById("monitor").value="";
}
function minus(){
operator="-";
 minus=parseFloat(document.getElementById("monitor").value);
 document.getElementById("monitor").value="";
}
function mul(){
operator="*";
 mul=parseFloat(document.getElementById("monitor").value);
 document.getElementById("monitor").value="";
}
function div(){
operator="/";
 div=parseFloat(document.getElementById("monitor").value);
 document.getElementById("monitor").value="";
}

function calculate(){
snumber=parseFloat(document.getElementById("monitor").value);
if(operator=="+"){
   result=plus+snumber;
   document.getElementById("monitor").value=result;
}
if(operator=="-"){
   result=minus-snumber;
   document.getElementById("monitor").value=result;
}
if(operator=="*"){
   result=mul*snumber;
   document.getElementById("monitor").value=result;
}
if(operator=="/"){
   result=div/snumber;
   document.getElementById("monitor").value=result;
}


}

</script>
 </body>
</html>