Toggle and display password.

jquery.togglepassword.js

$.fn.extend({
	togglePassword : function( config ){
		option = $.extend({
			"postfix" : "-text"
		}, config );
		sync = function(){
			var i = this.type.toUpperCase() === "PASSWORD" ?
				this.id + option.postfix : 
				this.id.replace( option.postfix, "" );
			$( "#" + i ).val( $(this).val() );
		};
		toggle = function(){
			if( this.checked ){
				$.data( this, "pswd" ).hide();
				$.data( this, "text" ).show();
			} else {
				$.data( this, "pswd" ).show();
				$.data( this, "text" ).hide();
			}
		};
		this.each( function(){
			var id, pswd, text, check, handlers;
			id = this.getAttribute( "data-for" );
			pswd = $("#" + id );
			text = $("#" + id + option.postfix );
			check = $(this);
			handlers = { keyup : sync, blur : sync };
			pswd.bind( handlers );
			text.bind( handlers );
			$.data( this, "pswd", pswd );
			$.data( this, "text", text );
			$(this).click( toggle );
			toggle.apply( this );
		});
	}
});

/* example :

<input type="password" id="pswd" name="pswd" />
<input type="text" id="pswd-text" name="pswd-text" style="display:none;" />
<input type="checkbox" id="pswd-toggle" name="pswd-toggle" data-for="pswd" />
<label for="pswd-toggle">パスワードを表示する</label>

<script>
$("#pswd-toggle").togglePassword();
</script>

*/