promptChar String(default: "_")

Specifies the character used to represent the absence of user input in the widget

Example - specify different prompt char

<input id="maskedtextbox" />
<script>
$("#maskedtextbox").kendoMaskedTextBox({
    mask: "000000",
    promptChar: " " //specify prompt char as empty char
});
</script>

Note that the promptChar should not be equal to any of the used mask literals in the mask value.