re = /<select(?:(?!<\/select)[\n\s\S])*data-level="2"[\n\s\S]*?<\/select>/m
str = '<div class="lsd-search-filter lsd-col-10">
<label for="lsd_search_10574_listdom-location">Regions</label>
<div class="lsd-hierarchical-dropdowns" id="lsd_search_10574_listdom-location_wrapper" data-for="listdom-location" data-id="lsd_search_10574_listdom-location" data-max-levels="2" data-name="sf-listdom-location" data-hide-empty="0">
<select class="listdom-location" name="sf-listdom-location" id="lsd_search_10574_listdom-location_1" placeholder="Select Region" data-level="1">
<option value="">Select Region</option>
<option class="lsd-option lsd-parent-0" value="289">Region 1</option>
<option class="lsd-option lsd-parent-0" value="391">Region 2</option>
<option class="lsd-option lsd-parent-0" value="290">Region 3</option>
</select>
<select class="listdom-location" name="" id="lsd_search_10574_listdom-location_2" placeholder="Select Region" data-level="2">
<option value="">Select Region</option>
<option class="lsd-option lsd-parent-289" value="291">Area 1</option>
<option class="lsd-option lsd-parent-289" value="292">Area 2</option>
</select>
</div>
</div>'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html