使用javascript / jquery将字符修复为文本输入框

Question

I am looking for a way to 'fix' a dollar symbol $ to a text input box eg <input type="text" value="$" /> but make it not possible for the default value to be removed, so that whatever the user inputs, there is always a $ symbol 'prepending' input.

Cheers

Answer 1

There is the possibility of a background-image but it's difficult to maintain, and doesn't react to font size changes, which makes it the less optimal choice IMO.

A better way in my opionion would be:

• Put a <span>$</span> next to the input (before it, actually).

• give it position: relative; left: 20px position: relative; left: 20px .

• The $ sign then moves into the input field.

• Then, give the input field padding-left: 24px .

• Voilá! The $ sign is in the input field, does not obscure anything, and cannot be removed.

Answer 2

Expanding on Pekka's answer, I used this on my page, but I automated it a little bit with jQuery. So for this example, all of the input fields that I want to put a $ symbol in, I give them a class of "cost".

CSS:

<style type=&quot;text/css&quot; media="screen">
.cost{
    position: relative;
    left: 20px;
}
input.cost{
    padding-left: 24px;
}
</style>

jQuery:

<script type="text/javascript">
$(document).ready(function(){    
    $("#lcce form input.cost").wrap('<div class=&quot;cost">');
    $("#lcce form input.cost").before('<span class="cost"></span>');
});
</script/>

This will place the span with a class of "cost" right before your input, and also wrap a div around both the input, and the span, so they are ensured to be on the same line.

If you don't have jQuery, you can get it from: jQuery.com

Now I've got a quick question - I noticed that with this styling, in IE6,7, and 8, the $ symbol is not lined up correctly. Does anybody out there have a fix for this?

Thank you!

Answer 3

I did it like this:

$('#price').keypress(function(event) {
var code = (event.keyCode ? event.keyCode : event.which);
if ($(this).val().indexOf('$') === -1){
    document.getElementById("price").value = "$" + $(this).val();
  } else {
    document.getElementById("price").value = $(this).val();
  }  
});

with <input type="text" id="price"> .

User can remove the dollar sign manually though if he/she wants to.

Answer 4

Is this as a visual effect only? If yes you could apply that with CSS as a background image on the input.

Afterwards, on the server, you can do whatever you want with the value (eg prepend it with $).

Answer 5

I too have been looking at different solutions for this. Using css to indent the text with padding and putting a background image in that position is your best bet.