Small issues in JS and CSS Loading

In the js script, there are two windows. onload
Copy codeThe Code is as follows:
Window. onload = function (){
Alert ("aaa ");
};

Window. onload = function (){
Alert ("bbb ");
};

Only one will be executed. This is the setting of the function itself. It is worth noting that the pop-up is not aaa, but bbb, and the last one is executed.

In the css file, in the css style
Copy codeThe Code is as follows:
# Checks {
Padding-left: 20px; padding-top: 16px; margin: auto;
}
# Checks {
Padding-left: 80px; padding-top: 38px; margin: auto;
}

It is also effective for the following style. If the padding-left in the second is removed, the padding-left in the first one is used.

HTML Tag

<Td style = "padding-left: 10px; padding-top: 8px; margin: auto;" style = "padding-left: 20px; padding-top: 16px; margin: auto; "> </td>

This is the first one to take effect. It is different from the two above.

I hope someone can explain it...