JavaScript dynamically determines html elements and performs different operations_javascript skills

In order to perform different operations on different elements in JavaScript, you need to judge the element that triggers the event in JavaScript, and then perform different operations.

Example:

html

Copy code The code is as follows:

javascript

Copy code The code is as follows :

Acquisition of the name and id attributes of the input is unsuccessful, but the value is OK. I don’t know why. What reason.

Reference:

Copy code The code is as follows:

var obj=document .getElementById("div1").getElementsByTagName("textarea")
for(var i=0;i{
if(obj[i].id==" aa")
{
alert(obj[i].innerText)
}
}