如何使表适合父div

试试这个:

#parent {
    border: 3px solid #f0f;
    width: 600px;       
}
table#child2 {    
    background: cyan; 
    table-layout:fixed;
    width: 100%;       
}
table#child2 td {
    white-space: normal;
    word-wrap: break-word;
}
td{
    border: 2px solid #666;    
}