src/html-amend.js
function afterElementOpen(input, element, content) {
            // Sanity check
            verifyParameterIsDefined(input, 'input', 'afterElementOpen');
            verifyParameterIsDefined(element, 'element', 'afterElementOpen');

            return insertAfter(normalizeValue(input), normalizeRegExp(`<${normalizeValue(element)}[^\>]*>`), normalizeValue(content));
        }
function afterElementOpen(input, element, content) {
            // Sanity check
            verifyParameterIsDefined(input, 'input', 'afterElementOpen');
            verifyParameterIsDefined(element, 'element', 'afterElementOpen');

            return insertAfter(normalizeValue(input), normalizeRegExp(`<${normalizeValue(element)}[^\>]*>`), normalizeValue(content));
        }
function afterElementOpen ( input , element , content ) { // Sanity check verifyParameterIsDefined ( input , 'input' , 'afterElementOpen' ) ; verifyParameterIsDefined ( element , 'element' , 'afterElementOpen' ) ; return insertAfter ( normalizeValue ( input ) , normalizeRegExp ( ` ${ normalizeValue ( element ) } \> ` ) , normalizeValue ( content ) ) ; }
Inserts content into the input string after the first occurrence of the element has been opened.

@param {String|Function} input the input to replace
@param {String|Function} element the element to insert after
@param {String|Function} [content] the content to insert within the input string
@return {String} a String which has the content added after the first occurrence of the element open tag within the input string
@throws {String} when input or element are not defined
Inserts content into the input string after the first occurrence of the element has been opened .