%%html
<!-- Heading -->
<h1>Grade Calculator</h1>
<h2>Input scores, press tab to add each new number.</h2>
<!-- Totals -->
<h3>
Total : <span id="total">0.0</span>
Count : <span id="count">0.0</span>
Average : <span id="average">0.0</span>
</h3>
<!-- Rows -->
<div id="scores">
<!-- javascript generated inputs -->
</div>
<script>
// Creates a new input box
function newInputLine(index) {
// Add a label for each score element
var title = document.createElement('label');
title.htmlFor = index;
title.innerHTML = index + ". ";
document.getElementById("scores").appendChild(title); // add to HTML
// Setup score element and attributes
var score = document.createElement("input"); // input element
score.id = index; // id of input element
score.onkeydown = calculator // Each key triggers event (using function as a value)
score.type = "number"; // Use text type to allow typing multiple characters
score.name = "score"; // name is used to group "score" elements
score.style.textAlign = "right";
score.style.width = "5em";
document.getElementById("scores").appendChild(score); // add to HTML
// Create and add blank line after input box
var br = document.createElement("br"); // line break element
document.getElementById("scores").appendChild(br); // add to HTML
// Set focus on the new input line
document.getElementById(index).focus();
}
// Handles event and calculates totals
function calculator(event) {
var key = event.key;
// Check if the pressed key is the "Tab" key (key code 9) or "Enter" key (key code 13)
if (key === "Tab" || key === "Enter") {
event.preventDefault(); // Prevent default behavior (tabbing to the next element)
var array = document.getElementsByName('score'); // setup array of scores
var total = 0; // running total
var count = 0; // count of input elements with valid values
for (var i = 0; i < array.length; i++) { // iterate through array
var value = array[i].value;
if (parseFloat(value)) {
var parsedValue = parseFloat(value);
total += parsedValue; // add to running total
count++;
}
}
// update totals
document.getElementById('total').innerHTML = total.toFixed(2); // show two decimals
document.getElementById('count').innerHTML = count;
if (count > 0) {
document.getElementById('average').innerHTML = (total / count).toFixed(2);
} else {
document.getElementById('average').innerHTML = "0.0";
}
// adds newInputLine, only if all array values satisfy parseFloat
if (count === document.getElementsByName('score').length) {
newInputLine(count); // make a new input line
}
}
}
// Creates 1st input box on Window load
newInputLine(0);
</script>
Js_Input • 6 min read
Description
Explanation of Js_Input
- Grade Calculator
- Input scores, press tab to add each new number.