Generally have a loved one died to wear a black armband, may I ask the origin of this custom, and wear is what to pay attention to?

Wearing a black armband at a funeral is a reference to Western civilization

Traditional Chinese culture is to white (the so-called mourning) as the tone of the funeral. And the western funeral more black wear black cuffs to black to send mourning. To this day, with the exchange and integration of world culture, these traditions have been slowly evolving, as for the funeral, wearing a black cuff to indicate the death of a loved one has slowly become a habit because it is not conducive to people's productive life.

China's 60's to carry out flat graves to return to the field, funeral rites simplified, wooden coffins from the speed of burial. 70's gradually implement cremation, wreaths, relatives wear a black cufflinks, the funeral from the simplified. 80's began to have a trend of restoration of the funeral.