Javascript RegExp: replace parameter value in query string
Task: change the value of parameter 'tid' in given querystring. Original querystring: var linkParam = 'tid=8&id=11008&location=news'; New 'tid' parameter value: var tagId = 12; You can do it using 'replace' function. Final code to replace: var tagIdReg = /[tid=](\d+)[&]/i; document.write(linkParam.replace(tagIdReg, '='+tagId+'&')); But if you need just extract 'tid' value use 'exec': var tagIdReg = /[tid=](\d+)[&]/i; var regResult = tagIdReg.exec(linkParam); document.write(regResult[1]);