防止android webview中的无效输入值更改

Question

I'm trying to prevent the change in input value for two cases.

If there is

1. multiple negative sign "-" eg. prevent typing of "-1-2-3"
2. multiple "." value eg. prevent typing of "1.2.3"

For desktop browser, I'm able to achieve using the following functions.

 function valueEntered(element, event){ var newVal = element.value if(event.code==="Minus") { if(element.value.length==0) return true // allow minus at start element.value = -1*parseFloat(newVal) // change the sign of number return false } else if(event.code==="Period") { if(element.value.indexOf('.')>-1) return false } return true }

 <input type="number" style="border-radius: 5px;" onkeypress="return valueEntered(this, event)" />

It's working perfectly fine. But if I use this snippet in android webview, it's not preventing as it should.

Answer 1

I trusted https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/code which tells that event.code will work for android webview also, but it doesn't.

Also event.key supports detecting numeric values only. If I type - , . , , ; the property event.key returns Unidentified .

Similarly, the property event.keyCode returns 229 for all keypress stated above.

So it is not actually possible to achieve what I want currently in android webview.