Created
May 13, 2017 21:57
-
-
Save eltonvs/b23ec72bab69b3d369553eb5e4e8dc60 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<!DOCTYPE html> | |
<html lang="en"> | |
<head> | |
<meta charset="UTF-8"> | |
<title>JS Expression Calculator</title> | |
</head> | |
<body> | |
<h1>Expression Calculator</h1> | |
Enter the expression: | |
<input id="expression" type="text" name="expression"> | |
<button id="calculate-expr" type="submit">Calculate</button> | |
<div class="result-area"> | |
Result: <strong id="expr-result">empty expression</strong> | |
</div> | |
<script> | |
let btn_calculate = document.getElementById('calculate-expr') | |
let expression = document.getElementById('expression') | |
let result_element = document.getElementById('expr-result') | |
let expression_pattern = /[0-9\(\)\-\/\*.\+\ ]+/ | |
btn_calculate.addEventListener('click', e => { | |
let expr_raw = expression.value.trim() | |
if (expression_pattern.test(expr_raw)) { | |
expr_result = eval(expr_raw) | |
} | |
result_element.textContent = typeof expr_result === 'number' ? | |
expr_result : "Error processing expression" | |
}) | |
</script> | |
</body> | |
</html> |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment