Use variable to replace all occurrences of specific string

Question

How do I use a dynamic variable as first argument in replace function?

I have this code that searches a user specified string:

 var query = jQuery.trim(jQuery(this).val()).toLowerCase();
 console.log(query + ' was searched')
 jQuery('.one-reference').each(function () {
 var jQuerythis = jQuery(this);
 if (jQuerythis.text().toLowerCase().indexOf(query) === -1) {
 jQuerythis.fadeOut();
 }
 else {
 jQuerythis.html(jQuerythis.html().replace(/&/g, '<strong>$&</strong>'));
 jQuerythis.fadeIn();
 }
 });

This replace(/&/g, '<strong>$&</strong>')) is not working.

I want to wrap all occurrences of query with <strong> tags.

• Anubhav: can you create a fiddle demonstrating the issue?
• Stefan: Shouldn't you then search for query instead of &?
• Umair Ayub: @Stefan it will search for the sting query then ... not the string inside variable it will search for
• Phrogz: FYI: your problem is unrelated to jQuery. String.prototype.replace is a standard JavaScript function.

Answer 1

As you're searching for an arbitrary value within the html you will need to create a RegExp object and use that in your replace.

if (jQuerythis.text().toLowerCase().indexOf(query) === -1) {
 jQuerythis.fadeOut();
} else {
 var queryReg = new RegExp(query, 'g');
 jQuerythis.html(jQuerythis.html().replace(queryReg, '<strong>$&</strong>'));
 jQuerythis.fadeIn();
}

Also you will first need to escape (\) any characters in your query variable that have a special meaning in regular expressions (^$[]+()\/- for example) -

query = query.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');

(from MDN)

See Regular Expressions at Mozilla Developer Network for a more in depth discussion on regular expressions.

• Stefan: Be sure to mention that inputting + or [] as parts of the query will mess around with the regex if they're not properly escaped.
• Shil Nevado: He could also use a function to clean the string query like: function replaceScapeChar(value) { return value.replace(/([\[|\]|\||\(|\)|\.|\*|\+|\{|\}|\$])/g, "\\1ドル") } (Maybe I didn't write ALL the scape characters. Add what I forgot :P)