javascript多次尝试捕获

Question

I read this article Multiple try-catch or one? and was wondering if there was a better way? Is there a way to just ignore the bad lines of code? My problem is I need to load multiple variables from objects that may or may not exist. Thanks everyone

 toparcv = document.getElementsByName("attribute[425]")[0].value; toparcv = document.getElementsByName("attribute[423]")[0].value; toparcv = document.getElementsByName("attribute[424]")[0].value; toparcv = document.getElementsByName("attribute[426]")[0].value; toparcv = document.getElementsByName("attribute[434]")[0].value; bottomarcv = document.getElementsByName("attribute[271]")[0].value; bottomarcv = document.getElementsByName("attribute[265]")[0].value; bottomarcv = document.getElementsByName("attribute[268]")[0].value; bottomarcv = document.getElementsByName("attribute[369]")[0].value; bottomarcv = document.getElementsByName("attribute[433]")[0].value; console.log(toparcv); console.log(bottomarcv);

im trying to read a textbox from a website that randomly generates the name from about 10 different names by adding 433 or 268.

Answer 1

You can cover all the bottommarcv assignments like this:

[271, 265, 268, 369, 433].forEach(function(num) {
    var list = document.getElementsByName("attribute[" + num + "]");
    if (list && list.length) {
        bottomarcv = list[0].value;
    }
});

This code pre-preemptively avoids an exception by checking the integrity of variables before referencing properties on them and because it's using a loop to examine each element, it can use only one if statement for all the values.

It is a little odd to be assigning them all to the same variable. Do you really only want the last one that has a value to be used here?