# To create custom attribute on input html element
**URL:** \
**Category:** Help Requests\
**Created:** [June 18, 2019, 4:08pm UTC](https://discourse.aurelia.io/t/to-create-custom-attribute-on-input-html-element/2658 "2019-06-18T16:08:08Z")\
**Posts on this page:** 4\
**Page:** 1
I want to create a custom attribute _input-format_
I can assign two values to the attribute that would enable me to clean the input string or to trim input string. Like below:
For value _clean_:
Trying to achieve declaring as below
```
```
The above should result me with the below embedded into the input element:
```
```
Similarly for _trim_
```
```
should result in:
```
```
where cleanString, trimString, are value converters and keypress function which are already declared as needed. I need help with creating custom attribute as I am not sure of getting the current _value_ bound to an html input element and also reassigning that to have all the above value converters and a function.
Can anyone please help me on achieving this? Appreciate your input and help.
This is where I stand:
```
import * as au from "aurelia-framework";
@au.autoinject
@au.customAttribute("input-format")
export class InputFormat {
constructor(element: Element) {
this.element = element;
}
@au.bindable
format: string;
formatChanged(name: string, newValue: string, oldValue: string) {
// need to have case statements
switch(name){
case 'clean':
// to assign the relevant value converter and the 'value' is to be passed into
// this assigment should result something like below
//
break;
case 'trim':
// to assign the relevant value converter the 'value' is to be passed into
//
break;
default:
// to leave the assigment as is
break;
}
}
// the select list
element: Element;
val: any;
}
```
here is the link where I am trying to put things together:
[sand box link](https://codesandbox.io/embed/custom-attribute-for-clean-string-xm531)
---
Could you please give me an example of how you would code that part. Like how would you let input element’s _value_ know to consider the evaluating ‘format’ option. Any working sandbox would be of great help so I can try out things.
---
have a look at the original updateTrigger behaviour [https://github.com/aurelia/templating-resources/blob/master/src/update-trigger-binding-behavior.ts](https://github.com/aurelia/templating-resources/blob/master/src/update-trigger-binding-behavior.ts)
There are also docs on custom binding behaviours