应用场景：做修改操作时，做复选框的选中状态。
<span>//</span><span>字段存的是id值，如 7,8,9 这些id值是需要被选中的</span>
<span>$checkId</span> = '7,8,9'<span>;
被循环的id值
</span><span>$idAll</span> = <span>array</span>('1','2','3','5','7','8','9'<span>);
// ',7,8,9,' ',1,'
</span><span>foreach</span>(<span>$idAll</span> <span>as</span> <span>$k</span>=><span>$v</span><span>){
</span><span>if</span>(<span>strpos</span>(','.<span>$checked</span>.',', ' , '.<span>$v</span>.','<span>) !== FALSE){
</span><span>$check</span> = 'checked="checked"'<span>;
}</span><span>else</span><span>{
</span><span>$check</span> = ''<span>;
}
}</span>
