Trying to do some jQuery validation (without the plugin - please no answers like "Just use the validate-js plugin").
I'm wiring up a client-side event handler keypress for each "required field" on doc ready:
$(document).ready(function() {
$('#myform input.required').each(function() {
$(this).keypress(onRequiredFieldKeyPress);
});
});
Which correctly fires this event on each keypress:
function onRequiredFieldKeyPress() {
if ($(this).val().trim() == '') {
$(this).next('em').html('*').show(); // show req field indicator
} else {
$(this).next('em').html('*').hide(); // hide req field indicator
}
}
But $(this).val() is always null/empty. Looks like it's passing in an "HTMLInputElement" which is what i'd expect, but it's almost like i have to project this into some other jQuery type?
Essentially i'm trying to do this: on the keypress event of any field which i have wired-up (which are all input elements), call that function. In that function, if that field has a value of '' (empty), then show a hidden field which displays a required field indicator.
I don't really care which actual element fired the keypress, as the behaviour of my logic will be the same. I just need to get the actual value.
Am i missing something?
Because you are using key-press event. Key press has 3 phase:
1. Key down: when key is press
2. Key hold: key is hold down
3. Key up: key is release
In your case, problem can be solved by using keyup event
$(document).ready(function() {
$('#myform input.required').each(function() {
$(this).keyup(onRequiredFieldKeyPress);
});
});
Try using event.currentTarget, where event is the first param of your function.
来源:https://stackoverflow.com/questions/3437893/jquery-keypress-how-to-get-value-of-input-which-triggered-event