What is the ruling on turban like scarf which girls/women have adopted now?
In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
The turban like scarf which women wear nowadays does not fulfil the compulsory requirements of covering the body, whether Hijaab in front of non Mahram males or even in Salaah.
The condition for women’s Salaah to be valid is that their hair and entire body should be covered. Hence, to perform the Salaah wearing such a scarf will invalidate one’s Salaah.. The face, hands till the wrists and feet (i.e. from below the ankles) do not have to be covered during Salaah.
As far as Hijaab in front on non Mahram males, it is compulsory for women to conceal their entire body, including the face. Allah Ta’ālā says in Surah al-Ahzāb, verse 53:
يَا أَيُّهَا النَّبِيُّ قُلْ لِأَزْوَاجِكَ وَبَنَاتِكَ وَنِسَاءِ الْمُؤْمِنِينَ يُدْنِينَ عَلَيْهِنَّ مِنْ جَلَابِيبِهِنَّ
O prophet, tell your wives and your daughters and the women of the believers that they should draw down their jilbāb (shawls) over them. (The jilbāb here refers to a piece of clothing large enough that it covers the entire body from head to toe).
This is also understood from many other Ayaats of The Quraan and Ahaadith.
You may further read The Issue of the Hijab of Women and its Boundaries