Practical javascript script for more practical check boxes_form effects

This is a very common effect on many websites, that is, clicking the checkbox of the general category will automatically select the checkboxes of all subcategories, or if all the checkboxes of the subcategories are selected, the general category checkbox will be selected. is also automatically selected.
I accidentally saw it on the msn website this time, so I tried to write it down myself.

<title></title> <center> <div style="width:90%;text-align:left;border:1px solid #ccc;height:25px;line-height:25px"> <input type="checkbox" id="d1" onclick="checkAll('1')"> </div>Leisure and entertainment<div style="width:90%;text-align:left;border:1px solid #ccc;" id="t1"> <input type="checkbox" onclick="fixChk('1')"> <input type="checkbox" onclick="fixChk('1')">Books and magazines <input type="checkbox" onclick="fixChk('1')">Music and Videos </div>Travel </center>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

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