esc_js( string $text ): string

Escapes single quotes, ", , &, and fixes line endings.

Description

Escapes text strings for echoing in JS. It is intended to be used for inline JS (in a tag attribute, for example onclick="..."). Note that the strings have to be in single quotes. The ‘js_escape’ filter is also applied here.

Parameters

$textstringrequired
The text to be escaped.

Return

string Escaped text.

More Information

See Data Validation for more information on escaping and sanitization.

Source

function esc_js( $text ) {
	$safe_text = wp_check_invalid_utf8( $text );
	$safe_text = _wp_specialchars( $safe_text, ENT_COMPAT );
	$safe_text = preg_replace( '/&#(x)?0*(?(1)27|39);?/i', "'", stripslashes( $safe_text ) );
	$safe_text = str_replace( "\r", '', $safe_text );
	$safe_text = str_replace( "\n", '\\n', addslashes( $safe_text ) );
	/**
	 * Filters a string cleaned and escaped for output in JavaScript.
	 *
	 * Text passed to esc_js() is stripped of invalid or special characters,
	 * and properly slashed for output.
	 *
	 * @since 2.0.6
	 *
	 * @param string $safe_text The text after it has been escaped.
	 * @param string $text      The text prior to being escaped.
	 */
	return apply_filters( 'js_escape', $safe_text, $text );
}

Hooks

apply_filters( ‘js_escape’, string $safe_text, string $text )

Filters a string cleaned and escaped for output in JavaScript.

Changelog

VersionDescription
2.8.0Introduced.

User Contributed Notes

  1. Skip to note 3 content

    I don’t really see the value of using esc_js() anymore. If you really have to do an inline script attribute, you may want to consider the following example with wp_json_encode() and esc_attr(), which seems easier to read and maintain:

    <?php
    $onfocus = sprintf( 
    	'if ( %s === this.value ) { this.value = ""; }',
    	wp_json_encode( $instance['input_text'] )
    );
    $onblur = sprintf(
    	'if ( "" === this.value ) { this.value = %s; }',
    	wp_json_encode( $instance['input_text'] )
    );
    ?>
    <input id="subbox" type="text" name="email"
    	value="<?php echo esc_attr( $instance['input_text'] ); ?>"
    	onfocus="<?php echo esc_attr( $onfocus ); ?>"
    	onblur="<?php echo esc_attr( $onblur ); ?>" />

    But in actuality, this specific example doesn’t need any PHP in its script attributes at all. The following should have the same result, thanks to the defaultValue property on the HTMLInputElement interface:

    <input id="subbox" type="text" name="email"
    	value="<?php echo esc_attr( $instance['input_text'] ); ?>"
    	onfocus="if ( this.defaultValue === this.value ) { this.value = ''; }"
    	onblur="if ( '' === this.value ) { this.value = this.defaultValue; }" />
  2. Skip to note 4 content

    Example

    Example of an input tag within a form displayed on the front-end of the site, generated from a widget. The first php segment is using esc_attr as it is an html attribute of input, while the next php segments is using esc_js within inline JavasSript.

    <input type="text" value="<?php echo esc_attr( $instance['input_text'] ); ?>" id="subbox" onfocus="if ( this.value == '<?php echo esc_js( $instance['input_text'] ); ?>') { this.value = ''; }" onblur="if ( this.value == '' ) { this.value = '<?php echo esc_js( $instance['input_text'] ); ?>'; }" name="email" />

    If you’re not working with inline JS in HTML event handler attributes, a more suitable function to use is wp_json_encode() , which is built-in to WordPress. (wp_json_encode() includes the string-delimiting quotes for you):

    var title = <?php echo wp_json_encode( $instance['title'] ) ?>;

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