仿PHP 中的strpos()用indexOf()方法

function strpos (haystack, needle, offset) {
       var i = (haystack+'').indexOf(needle, (offset || 0));
       return i === -1 ? false : i;
   }
       var temp2 = strpos (temp,'' )
       if (temp2 !== false ) {
           console.log('包含空字符');
}