focus-blur.js

来自「这是《JavaScript学习源代码》一书的源代码」· JavaScript 代码 · 共 12 行

// a function to react to the FOCUS event
function wipe(box)
{
  box.value=""; 
}

// a function to react to the BLUR event
function check(box, str)
{ 
  if(box.value=="") alert("Enter a " + str); 
}