Update HTML string validation
Update HTML string validation

hongtoushizi/phpwkhtmltopdf,hongtoushizi/phpwkhtmltopdf,ProPheT777/phpwkhtmltopdf,jl9n/phpwkhtmltopdf,jl9n/phpwkhtmltopdf,serjee/phpwkhtmltopdf,mikehaertl/phpwkhtmltopdf,mikehaertl/phpwkhtmltopdf,serjee/phpwkhtmltopdf,ProPheT777/phpwkhtmltopdf