input组件placeholder-class设置无效

<input class='com_f_r_c_s defaultInputView' style="{{inputStyle}}" value="{{value}}" placeholder="{{placeholder}}" placeholder-class="comPlaceholderStyle" maxlength='{{maxlength}}' type='{{type}}' confirm-type='{{confirm_type}}' bindinput='{{bindinput}}' bindfocus="{{bindfocus}}" bindblur="{{bindblur}}" id="{{id}}" disabled="{{disabled}}">input

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