javascript odd/even in a form
Question
I am unable to make simple javascript that take a number in the textbox and whne the button is clicked it returns the result.
<html>
<head>
<body>
<form>
<input id = "evenoddinput" >
<input type="button" value="check" OnClick="check();">
</form>
<script>
function check()
{
var v=document.getElementById("evenoddinput").value;
if(v%2==0)
{
} document.write("Even");
else
{
document.write("odd");
}
}
</script>
</body>
</html>
3 answers
solution1
4 ACCPTED 2016-05-26 11:00:00
Correct syntax to select element by id attribute is getElementById not getValueById .
Also use console.log() for debugging.
function check() { var v = document.getElementById('evenoddinput').value; if (v % 2 == 0) { console.log("Even"); } else { console.log("odd"); } }
<form> <input id="evenoddinput"> <input type="button" value="check" OnClick="check();">
solution2
0 2016-05-26 11:02:38
Your code is wrong it must be
var v=document.getElementById("evenoddinput").value;
Not
var v=document.getValueById(evenoddinput).value;
solution3
0 2016-05-26 11:11:44
It is not recommended to write into page using document.write . Because it will replace entire page content. It is better to use a result field and write result to this field as innerHTML .
function check() { var v = document.getElementById('evenoddinput').value; var result; if (v % 2 == 0) { result = "Even"; } else { result = "odd"; } document.getElementById("result").innerHTML = result; }
<input id="evenoddinput"> <input type="button" value="check" OnClick="check();"> <div id="result"></div>
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