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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

            
              <link href='//fonts.googleapis.com/css?family=Bungee' rel='stylesheet'>
<div class='container'>
  <div id='calculator'>

    <!-- TITLE -->

    <div id='title' class='text-center'>
      <h5><b>Simple Calculator</b></h5>
    </div>

    <!-- ENTRY BOX -->

    <div id='entrybox' class='text-right'>
      <div id='entry'>
        <p id='result'>0</p>
      </div>
      <div id='history'>
        <p id='log'>0</p>
      </div>
    </div>

    <!-- BUTTONS -->

    <div id='buttons'>

      <button class='red btn-danger' value='ac'>AC</button>
      <button class='red btn-danger' value='back'>&#8678;</button>
      <button class="btn-primary" value='/'>&divide;</button>
      <button class="btn-primary"value='*'>x</button>
      <button class="btn-info"value='7'>7</button>
      <button class="btn-info"value='8'>8</button>
      <button class="btn-info"value='9'>9</button>
      <button class="btn-primary"value='-'>-</button>
      <button class="btn-info"value='4'>4</button>
      <button class="btn-info"value='5'>5</button>
      <button class="btn-info"value='6'>6</button>
      <button class="btn-primary" value='+'>+</button>
      <button class="btn-info"value='1'>1</button>
      <button class="btn-info"value='2'>2</button>
      <button class="btn-info"value='3'>3</button>
      <button class="btn-info"id='zeroButton' value='0'>0</button>
      <button class="btn-info"value='.'>.</button>
      <button class="btn-primary"id='equalButton' value='='>=</button>

    </div>
    <!-- end buttons -->
  </div>
  <!-- end calculator -->
</div>
<footer><a>Free Code Camp Rocks!</a></footer>
            
          
!

CSS

            
              /* Credit: some CSS Codes are adapted from Justin Woodward's (https://codepen.io/freeCodeCamp/full/rLJZrA) */

body {
  font-family: 'Bungee';
	background-image: url(http://wallup.net/wp-content/uploads/2016/01/167565-abstract-dark-black_background-digital_art-artwork.png);
	background-size: 100%;
}

#calculator {
  height: 440px;
  width: 300px;
  margin-top: 10%;
  margin-left: auto;
  margin-right: auto;
  background-color: white;
  border: 2px solid #908b85;
  border-radius: 20px;
  box-shadow: 7px 10px 34px 1px rgba(0, 0, 0, 0.68), inset -1px -6px 12px 0.1px #89847e;
}

#title {
  padding-top: 10px;
  padding-bottom: 10px;
}

#entrybox {
  width: 85%;
  height: 100px;
  margin-left: auto;
  margin-right: auto;
  border: 2px solid #b4b39d;
  border-radius: 6px;
  background-color: yellow;
	overflow: auto;
}

#entry {
  margin-right: 10px;
  font-size: 35px;
}

#buttons {
  font-size: 16px;
  font-weight: bold;
  color: #fff;
  position: absolute;
  display: inline-block;
  width: 280px;
  height: auto;
  margin-top: 15px;
  margin-left: 15px;
}

button {
  border-radius: 8px;
  border: none;
  background-color: #3a3a3a;
  margin: 0 4px 10px 8px;
  height: 40px;
  width: 50px;
  box-shadow: 0px 3px 0px 0px #222121, inset -1px -3px 10px 1px #515151;
	font-weight: bold;
}

.btn-info{
	color: black;	
}

.btn-info:hover{
	color: yellow;
	font-size:110%;
}

button:active {
  transform: translate(0px, 3px);
  box-shadow: none;
}

.row {
  margin-top: 20px
}

#topAdjust {
  margin-top: -52px;
}

#equalButton {
  position: absolute;
  margin-left: 12px;
  margin-top: -50px;
  height: 90px;
}

#zeroButton {
  width: 117px;
}

.red {
  font-size: 14px;
  background-color: #a72d45;
  box-shadow: 0px 3px 0px 0px #671c2a;
}

footer {
  font-family: 'Arial Black';
	color: white;	
  position: relative;
  font-size: 16px;
  font-weight: normal;
  margin-top: 20px;
	margin-left: auto;
	margin-right:auto;
  width: 300px;
  height: 40px;
	text-align: center;
}

button,
button:hover,
button:active,
button:visited {
  text-decoration: none !important;
  outline: none !important;
}

a,
a:hover,
a:active,
a:visited {
  color: #922031;
  text-decoration: none !important;
  outline: none !important;
}

#history {
  /*transform: translate(-13px, -17px);*/
  position: relative;
  height: 10px;
  bottom: 17px;
  margin-right: 14px;
  color: #8b8b7b;
  font-size: 12px;
}
            
          
!

JS

            
              $(document).ready(function() {
	// Declare variables
	var entry="";
	var memory=[];
	var result=0;
	var operator = /(\+|-|\*|\/|=)/g;
	var digit = /[0-9]/;
	var doubleDot = /(\..\.)/;
	var isDigit, isOperator, isDot, isAC, isBack;
	var isLastDigit, isLastOperator, isLastDot;
	isLastDigit=isLastOperator=isLastDot=false;
	
	// Function: obtain key press
	$("button").click(function(){
		entry	= $(this).attr("value");		
		checkEntry();
		displayCurrent();	
		checkRules();
		displayHistory();
			
	})
	
// flag the input with the appropriate entry type	
	function checkEntry(){
		entry.match(digit)===null? isDigit=false : isDigit=true
		entry.match(operator)===null|entry.match(operator)===undefined? isOperator=false : isOperator=true
		entry==="."?isDot=true:isDot=false
		entry==="ac"?isAC=true:isAC=false
		entry==="back"?isBack=true:isBack=false
		// console.log(isBack);
			
		if (memory.length>0){
			memory[memory.length-1].match(digit)===null? isLastDigit=false :  isLastDigit=true
			memory[memory.length-1].match(operator)===null | memory[memory.length-1].match(operator)===undefined? isLastOperator=false :  isLastOperator=true		
			memory[memory.length-1].match(/(\.)/g) ? isLastDot=true :  isLastDot=false
		}	
//		console.log(isLastDot);
		
		if(memory[memory.length-1]=="="){
			memory=[];
			memory.push(result);
			}

	}
	
	// Function: check key press against rules
	function checkRules(){				
		if (isAC){
			memory=[];
			displayHistory();
			result=0;
			displayCurrent();
//			console.log(entry);
		} else if (isBack){
			if(memory.length>0){
				memory.pop();
				displayHistory();
				displayCurrent();
			}
		} else if (entry=="="){
			getResult();	
		}	else if (isOperator){
			if (isLastOperator&&memory.length>1) {memory[memory.length-1]=entry;}
			else if (memory.length==0&&entry!=="-"){} else {memory.push(entry);}
		} else if (isDot){
			if (memory.length==0) {memory.push("0."); }
			else if (result!=0&&isLastDot){$("#result").text("Wrong Key");}
			else if (!isLastDot&&isLastDigit) {memory[memory.length-1]+=entry;}			
			else {memory.push(entry);}
		} 
//		else if (memory[memory.length-1]=="." | memory[memory.length-1] % 1 == 0){console.log("strange");}
		else { 
			// Assuming isDigit
//			console.log(isLastDigit);
			if (memory.length==0) {memory.push(entry);}
			else if (memory.length==1&&memory[0]=="-"){memory[0]="-"+entry;}
			else if (isLastDigit) {memory[memory.length-1]+=entry;}
			else {memory.push(entry); }
		}
		
	}
	
	// Function: display current button being pushed
	function displayCurrent(){		
		if (memory.length>0){
			$("#result").text(result);
		}	else {$("#result").text("0");}			
	}
	
	// Function: display history
	function displayHistory(){
		if (memory.length>0&&memory[memory.length-1]=="="){
				$("#history").text(result);
				}
		else if (memory.length>0){
			$("#history").text(memory.join(""));
			}	
		else {$("#history").text("0");}	
	}
		
	// Function: getResult
	function getResult(){
//		console.log(memory);
//		Please keep in mind that the eval() function isn't the most efficient
// It has vulnerabilities; thus, another method should be used to replace this function
		result=eval(memory.join(""));
		if (result%1!==0){
			result = result.toString();  // this neat little trick will ommit all non-significant trailing zeros after the decimal point
		}
		memory.push("=");
		$("#result").text(result);
//		$("#history").text(memory.join(""));
	}
		
})
            
          
!
999px

Console