<input type="text"></input>
<script>
var a = document.getElementsByTagName('input')[0];
a.onkeypress = function(evt) {
this.evt = evt || event;
var b = String.fromCharCode(evt.keyCode);
while(forEach(evt) {
alert("You pressed " + b);
}
};
</script>
This doesn't seems to be working. It should always alert the key when user presses a key. The browser here is Chrome.
It's not working because you're calling a function you don't define (forEach), here:
while(forEach(evt) {
// ^
If you look in the JavaScript console, you'll see an error related to that.
Also, you don't want to assign to an evt property on this:
this.evt = evt || event; // <== Don't do this
Just use the argument:
evt = evt || event;
And there's no reason for a loop if you're going to alert every keypress individually.
Also, input elements don't have closing tags. It should just be:
<input type="text">
or (in XHTML, and optionally in HTML):
<input type="text"/>
not:
<input type="text"></input>
And finally, note that some browsers use which for the keycode, others use keyCode. You can use || to use whichever the browser supplies:
String.fromCharCode(evt.which || evt.keyCode)
Here's a minimal update: Live Copy | Live Source
<input type="text">
<script>
var a = document.getElementsByTagName('input')[0];
a.onkeypress = function(evt) {
evt = evt || event;
alert("You pressed " + String.fromCharCode(evt.which || evt.keyCode));
};
</script>
不需要while循环。只需以跨浏览器兼容的方式获取密钥，找到它的等效字符并警告它。
var a = document.getElementsByTagName('input')[0];
a.onkeypress = function(event) {
//e.which & e.keyCode are for cross browser compliance
alert(String.fromCharCode(event.keyCode || event.which));
};