numeric keypad is also feasible. If you want to customize the 26-key keyboard, you can't just enter letters, right? If you want to lose Chinese, you have to achieve a complete set of input method functions. What can you do badly when you have this time

there is no difficulty in this. The train of thought (note) is about as follows:

input box forbids the pop-up input method text | input readonly of number, etc.
customize the click / touch event of the keyboard and then correspond to the generated string to display the corresponding input value.
string processing
event, data processing 2 important points

Pinyin Library = >

customize a pinyin library. This must be incomplete .

 var obj =  {
"a":"",
"b":"",
    ...
}

then match the English you typed (that is, the phonetic alphabet)

write a custom input box, but do not use input, to achieve the same effect as input, and then customize an animated cursor effect. Click somewhere, the custom keyboard appears

the difficulty is: you use letters to form words,