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? Se un campo di input contiene dati non validi, visualizza un messaggio: https://www.w3schools.com/js/tryit.asp?filename=tryjs_validation_check <!DOCTYPE html> <html> <body> <p>Enter a number and click OK:</p> <input id="id1" type="number" min="100" max="300" required> <button onclick="myFunction()">OK</button> <p>If the number is less than 100 or greater than 300, an error message will be displayed.</p> <p id="demo"></p> <script> function myFunction() { var inpObj = document.getElementById("id1"); if (!inpObj.checkValidity()) { document.getElementById("demo").innerHTML = inpObj.validationMessage; } else { document.getElementById("demo").innerHTML = "Input OK"; } } </script> </body> </html> ' Se il numero in un campo di input ? maggiore di 100 (l' max attributo di input ), visualizza un messaggio: https://www.w3schools.com/js/tryit.asp?filename=tryjs_validation_rangeOverflow <!DOCTYPE html> <html> <body> <p>Enter a number and click OK:</p> <input id="id1" type="number" max="100"> <button onclick="myFunction()">OK</button> <p>If the number is greater than 100 (the input's max attribute), an error message will be displayed.</p> <p id="demo"></p> <script> function myFunction() { var txt = ""; if (document.getElementById("id1").validity.rangeOverflow) { txt = "Value too large"; } else { txt = "Input OK"; } document.getElementById("demo").innerHTML = txt; } </script> </body> </html> |