Develop Reference

Check if text is selected on keydown event

I have a scenario where i prevent user from entering 2nd numeric after a decimal.I have my code on keydown event.
Below is my code:
$scope.Inputkeydown = function (event, value) {
if (event.keyCode != 8) {
if (value != null && value != undefined && value != "") {
var regex = /^\d*\.\d$/; //this regex passes only decimal numbers with one digit after decimal
if (regex.test(value)) {
event.preventDefault();
}
}
}
};
Now the trouble is if user selects on the text(say 50.0) in the textbox and say presses 5 at that time it is getting prevented too, as in the textbox value is 50.0 and regex allows it go and it is getting prevented from being typed in.
Can i check on keydown if text is being copied?? or is there any other way around?

Instead of preventing the user from entering it, you could just remove it after keypress:
function filterDecimals(inp) {
return inp.replace(/^(\d*\.\d)\d*$/g, '$1');
}
Or, if you want to remove everything after it, replace the second \d* with .*
EDIT (example of usage)
This function takes the text as input and returns the new filtered text. To use this, just attach an event handler on keypress like so:
<input type="text" id="filteredbox">
<script>
var txt = document.getElementById("filteredbox");
// on keyup event (you can change to keypress if you want, but this is more logical here
txt.addEventListener("keyup", function(){
// sets value of txt to the returned data from filterDecimals()
// if statement: only filters it if necessary; this eliminates the "selected text" issue you mentioned
if (this.value !== filterDecimals(this.value)) {
this.value = filterDecimals(this.value);
}
});
</script>

How to make an input restriction function using jquery

I want to do is put a character and length restriction in an input using this rules:
A combination of at least ten numbers, letters and punctuation marks
(like ! and &)
and if the user didnt complete the rules the input value will be back to empty again.
My problem is I'm still a beginner and my current code wont work as i wanted. Can anyone help me with this please.
Current output: http://jsfiddle.net/5kcsn/271/
Script:
$(document).ready(function () {
$('#example').on('blur', function () {
$('#example').change(inputVerify);
inputVerify()
})
$('#example').on('keydown', function () {
$('#example').change(inputVerify);
inputVerify()
})
$('#example').change(inputVerify);
function inputVerify(value) {
return /^(?=.*[!##$%^&*])[a-zA-Z0-9!##$%^&*]{10,20}$/.test(value) && /[a-z]/.test(value) && /\d/.test(value)
};
});

I don't want to tell you "how to do it better in general", but what about giving live feedback instead of reverting a bad entry? This way the user can a) see as soon as it is correct, b) correct his former entry:
$("#example").on('keydown',function(){
if(!inputVerify($("#example").val())){
$("#example").css("border","1px solid red");
} else {
$("#example").css("border","1px solid black");
}
});
function inputVerify(value){
return /^(?=.*[!##$%^&*])[a-zA-Z0-9!##$%^&*]{10,20}$/.test(value)
&& /[a-z]/.test(value)
&& /\d/.test(value)
};

You should really do this only on blur, it should look something like this:
$(document).ready(function(){
$('#example').on('blur', function(){
if( !inputVerify() ) {
$(this).val('');
}
});
});
function inputVerify(value){
return /^(?=.*[!##$%^&*])[a-zA-Z0-9!##$%^&*]{10,20}$/.test(value)
&& /[a-z]/.test(value)
&& /\d/.test(value)
};
You see, your inputVerify function returns true or false and you would have to remove the input yourself by $(this).val('');.
The jsFiddle: http://jsfiddle.net/5kcsn/272/
Please note that I have not tested your regex, as I am not too familiar with them, yours seem to work though.

Try this, note I did not check your regular expression:
$(document).ready(function () {
$('#example').keydown(inputVerify);
function inputVerify(event) {
var value = $(this).val();
if (!(/^(?=.*[!##$%^&*])[a-zA-Z0-9!##$%^&*]{10,20}$/.test(value)
&& /[a-z]/.test(value)
&& /\d/.test(value))) {
$(this).val('');
}
};
});
Link to JSFiddle
The function inputVerify catches the event passed by the keydown handler and uses the $(this) which refers to the element the event is triggered on to get the value of the input.
And then, if the regex tests fail, empty the input.

Disable spaces in Input, AND allow back arrow?

I am trying to disable spaces in the Username text field, however my code disables using the back arrow too. Any way to allow the back arrow also?
$(function() {
var txt = $("input#UserName");
var func = function() {
txt.val(txt.val().replace(/\s/g, ''));
}
txt.keyup(func).blur(func);
});
fiddle: http://jsfiddle.net/EJFbt/

You may add keydown handler and prevent default action for space key (i.e. 32):
$("input#UserName").on({
keydown: function(e) {
if (e.which === 32)
return false;
},
change: function() {
this.value = this.value.replace(/\s/g, "");
}
});
DEMO: http://jsfiddle.net/EJFbt/1/

This seems to work for me:
<input type="text" onkeypress="return event.charCode != 32">

It doesn't "disable" the back arrow — your code keeps replacing all the text outright, whenever you press a key, and every time that happens the caret position is lost.
Simply don't do that.
Use a better mechanism for banning spaces, such as returning false from an onkeydown handler when the key pressed is space:
$(function() {
$("input#Username").on("keydown", function (e) {
return e.which !== 32;
});​​​​​
});
This way, your textbox is prohibited from receiving the spaces in the first place and you don't need to replace any text. The caret will thus remain unaffected.
Update
#VisioN's adapted code will also add this space-banning support to copy-paste operations, whilst still avoiding text-replacement-on-keyup handlers that affect your textbox value whilst your caret is still active within it.
So here's the final code:
$(function() {
// "Ban" spaces in username field
$("input#Username").on({
// When a new character was typed in
keydown: function(e) {
// 32 - ASCII for Space;
// `return false` cancels the keypress
if (e.which === 32)
return false;
},
// When spaces managed to "sneak in" via copy/paste
change: function() {
// Regex-remove all spaces in the final value
this.value = this.value.replace(/\s/g, "");
}
// Notice: value replacement only in events
// that already involve the textbox losing
// losing focus, else caret position gets
// mangled.
});​​​​​
});

Try checking for the proper key code in your function:
$(function(){
var txt = $("input#UserName");
var func = function(e) {
if(e.keyCode === 32){
txt.val(txt.val().replace(/\s/g, ''));
}
}
txt.keyup(func).blur(func);
});
That way only the keyCode of 32 (a space) calls the replace function. This will allow the other keypress events to get through. Depending on comparability in IE, you may need to check whether e exists, use e.which, or perhaps use the global window.event object. There are many question on here that cover such topics though.
If you're unsure about a certain keyCode try this helpful site.

One liner:
onkeypress="return event.which != 32"

How to use jQuery to prevent the space key from entering a space?

I thought it would be a simple thing to hijack the space key when in a form input so that it would function like a hyphen. Generally jQuery makes stuff like this really simple.
The code I tried is this:
$("#StreamUrl").keydown(function (e) {
if (e.keyCode == 32) return 109;
});
But this has no effect whatsoever. I tried a more simple script:
$("#StreamUrl").keydown(function (e) {
//if (e.keyCode == 32) return 109;
alert(e.keyCode);
});
This script correctly alerts 32 on space press and 109 on hyphen press. Also, I have no JavaScript errors.
Why wouldn't if (e.keyCode == 32) return 109; work? When I replace that line with if (e.keyCode == 32) alert("space!!"); I get the alert correctly, so I know the if is returning true correctly.
What gives?
Edit - Solution
Thanks to #Nick for pointing out the copy-paste issue. I ended up with a little bit of a hybrid. Here's the code that I have gotten to work which is both smooth and handles Copy/Paste.
$("#StreamUrl").keydown(function (e) {
if (e.keyCode == 32) {
$(this).val($(this).val() + "-"); // append '-' to input
return false; // return false to prevent space from being added
}
}).change(function (e) {
$(this).val(function (i, v) { return v.replace(/ /g, "-"); });
});

The problem is that return 109 doesn't do what you want it to do. In an event handler, you return true or false depending on whether or not you want the browser to execute the default action. In keydown, you would return false to prevent the character from being inserted.
$("#StreamUrl").keydown(function (e) {
if (e.keyCode == 32) {
$(this).val($(this).val() + "-"); // append '-' to input
return false; // return false to prevent space from being added
}
});
jsfiddle example

You usually want the keyup event instead here, which fires after the space has been added, something like this is a bit easier:
$("#StreamUrl").bind("keyup change", function () {
$(this).val(function(i, v) { return v.replace(/ /g,"-"); });
});
Try it out here, what this does is allow the space to be added, but then instantly does a replace of spaces for hyphens by passing a function to .val(). For older versions of jQuery, it'd look like this:
$("#StreamUrl").bind("keyup change", function () {
$(this).val($(this).val().replace(/ /g,"-"));
});
This works even for people pasting content, an easy way to get around keydown validation.

Create an autocompleter like the Facebook status update

I'm trying to create a div with contenteditable like the Facebook status update. Then I mean I want to show an autocomplete box when the user have written #.
How would you do that. Currently I'm just playing with keypress and check if the keycode = 64. Somehow that works, but it doesn't validate if there's a space before the alfa, or if the user has unfocused the box, then focused it again.
Any ideas? Or do you know about any plugin that works something like that?
Tnx

I'd probably do it with keypress too.
but we need to check the cursor position to check the character before the '#'.
here's the function I used from http://javascript.nwbox.com/cursor_position/cursor.js
function getSelectionStart(o) {
if (o.createTextRange) {
var r = document.selection.createRange().duplicate();
r.moveEnd('character', o.value.length);
if (r.text == '') return o.value.length
return o.value.lastIndexOf(r.text);
} else {
return o.selectionStart;
}
}
then with jquery I wrote this keypress callback function:
txt.keypress(function(event) {
if (event.which == 64) {
var index = getSelectionStart(this)
var prevChar = txt.val().substring(index - 1, index);
// now you can check if the previous char was a space
}
});