(function(){
var mobile = /android|iphone/.test(navigator.userAgent)
var textarea = document.querySelector('textarea')
textarea.onkeydown = function(e) {
mobile && (textarea.value = toLowerCaseFirstStr(textarea.value))
}
})()
function toLowerCaseFirstStr(e) {
return e && (e[0].toLowerCase() + e.slice(1))
}