# Bad value X for attribute “src” on element “script”: Illegal character in query: “"” is not allowed.
> Canonical HTML version: https://rocketvalidator.com/html-validation/bad-value-x-for-attribute-src-on-element-script-illegal-character-in-query-quote-is-not-allowed
> Attribution: Rocket Validator (https://rocketvalidator.com)
> License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
When the browser's HTML parser encounters a `src` attribute, it expects the value between the opening and closing quotes to be a valid URL. URLs have strict rules about which characters are permitted — a literal double quote (`"`) is not one of them. If a `"` character appears inside the URL, the validator flags it as an illegal character in the query string (or other parts of the URL).
This error often doesn't stem from an intentionally embedded quote in the URL itself. Instead, it's usually a symptom of malformed HTML around the attribute. Common causes include:
- **Stray quotes after the attribute value**, such as writing `src="https://example.com/script.js"async""` instead of properly separating attributes.
- **Accidentally doubled closing quotes**, like `src="https://example.com/script.js""`.
- **Boolean attributes given empty-string values incorrectly**, such as `async""` instead of just `async`, which causes the parser to interpret the extra quotes as part of the preceding `src` value.
- **Copy-paste errors** that introduce smart quotes (`"` `"`) or extra quotation marks into the URL.
This matters for several reasons. Malformed `src` attributes can cause the script to fail to load entirely, breaking functionality on your page. It also violates the HTML specification, which can lead to unpredictable behavior across different browsers as each parser tries to recover from the error differently.
To fix the issue, carefully inspect the `
```
### Incorrect — doubled closing quote
Here, an extra `"` at the end of the `src` value creates an illegal character in the URL:
```html
```
### Incorrect — smart quotes from copy-paste
Curly/smart quotes copied from a word processor are not valid HTML attribute delimiters and get treated as part of the URL:
```html
```
### Correct — clean attributes with proper quoting
```html
```
### Correct — boolean attribute written as a bare keyword
Boolean attributes like `async` and `defer` don't need a value. Simply include the attribute name:
```html
```
While `async="async"` is technically valid per the spec, the cleanest and most common form is the bare attribute. Avoid empty-string patterns like `async=""` placed without proper spacing, as they can lead to the exact quoting errors described here.
### Correct — full valid document
```html
Valid Script Example
Page content here.
```
If you're generating `