I want to show an alert when the text box input of the first name is empty.
Javascript Code
<script>
function validation() {
var fname = document.getElementByID("fname").value;
if ( fname== "")
alert("Enter First Name");
}
</script>
HTML Code
<form>
First name:
<input type="text" id="fname">
<br/><br/>
<button id="btnSubmit" onclick="validation()">Submit</button>
<button id="btnReset">Reset</button><br/>
<button id="btnMenue"><a href= "index.php">Menue</a></button>
</form>
I have tried related articles but they didn't solve my problem.
Two issues in your code:
getElementByID
should be getElementById
preventDefault
on it to stop the default behaviour that is stop form submission. function validation(e) { var fname = document.getElementById("fname").value; // Typo here ID should be Id. if (fname == "") { e.preventDefault(); alert("Enter First Name"); } }
<form> First name: <input type="text" id="fname"><br/><br/> <button id="btnSubmit" onClick="validation(event)">Submit</button> <button id="btnReset">Reset</button><br/> <button id="btnMenue"><a href= "index.php">Menue</a></button> </form>
document.getElementByID is not a function
, you have a type in your code:
getElementByID
<- last letter is big in you code, should be small getElementById
working example
function validation() { // big D, throws error // var fname = document.getElementByID("fname").value; var fname = document.getElementById("fname").value; console.log(fname); if (fname == "") alert("Enter First Name"); }
<form> First name: <input type="text" id="fname"><br/><br/> <button id="btnSubmit" onclick="validation()">Submit</button> <button id="btnReset">Reset</button><br/> <button id="btnMenue"><a href= "index.php">Menue</a></button> </form>
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