Javascript passing data between text boxes
Question
I'm working on getting data to go from one textbox to another using javascript. Im new to Javascript and im getting a document undefined or null error.
<!DOCTYPE html>
<html>
<head>
<script>
function doit() {
window.document.form1.txtbox1.value= window.document.form2.txtbox2.value;
}
</script>
</head>
<body>
<form name="form1">
Enter your name:
<input type="text" name="txtbox1" value="">
<input type="button" name="btn1" value="Click" onclick="doit()">
</form>
<br><br><br>
<form name="form2">
Results:
<input type="text" name="txtbox2" value="">
</form>
</body>
</html>
3 answers
solution1
0 2018-02-24 15:03:35
It seems that you are trying access the element as a property of the DOM.
Instead, you should use document.getElementsByName method.
Revised function:
function doit(){
// The [0] is for accessing the first item.
// If you are unfamiliar with arrays, visit
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
document.getElementsByName("txtbox1")[0].value = document.getElementsByName("txtbox2")[0].value;
}
solution2
0 2018-02-24 15:03:47
You need to switch (swap) them : window.document.form1.txtbox1.value= window.document.form2.txtbox2.value;
When you click a button - you set the value of the second input to the first one and probably the second input called 'Result' is empty.
Try:
function doit() {
window.document.form2.txtbox2.value = window.document.form1.txtbox1.value;
}
There should not be any error, it's just pass data in another direction as you probably expect.
solution3
0 2018-02-24 15:06:01
Give a unique ID to both the input element.
<input type="text" id="txtbox1" value="">
<input type="text" id="txtbox2" value="">
and in function doit()
document.getElementById("txtbox2").value = document.getElementById("txtbox1").value
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