I have a textbox, and whenever the value of the box changes, I want to check and see if 20 digits have been entered.
I thought that I would use the onChange
event, but this seems to be interpreted as the onBlur
event on IE.
So then I thought I would use onKeyDown
, but the problem comes in if the user wants to paste a value into the field, then the function never gets called.
There are no other form boxes so I can't rely on onBlur
or expect that they will change focus ever.
How do I do this?
I just want to evaluate the value of the textbox every time the value of the textbox changes.
<input type="text" onKeyDown="myfunction()">
An effective way is to use a combination of onkeydown
and onpaste
, which will work in IE, Firefox, Chrome and Safari. Opera is the odd one out here because it doesn't support onpaste
so you may have to fall back to onchange
for Opera or use the DOMAttrModified
mutation event, see example below.
Internet Explorer also supports onpropertychange
, which will fire every time a property changes on an element -- including value
. I have read that DOMAttrModified
is supported by Opera and Safari (not sure about Firefox), so you could use that in combination with IE's onpropertychange
(untested):
if ("implementation" in document &&
document.implementation.hasFeature('MutationEvents','2.0'))
myInput.addEventListener("DOMAttrModified", valueChanged, false);
else if ("onpropertychange" in myInput)
myInput.onpropertychange = valueChanged;
function valueChanged (evt)
{
var attr;
evt = evt || window.event;
attr = evt.attrName || evt.propertyName;
if (attr == "value")
validate();
}
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