Javascript compatibility in IE and Firefox _ javascript skills

If you want to learn JavaScript, you must know or understand it. 1. You can find that the id attribute of the input tag under IE is the same as the name attribute by default, firefox must specify the name of the id attribute; otherwise, the id attribute cannot be used.
For example:
The following code in IE can be executed, but not in Firefox:
Script
Alert (document. getElementById ("username"). value );
Script
The following code must be changed:

Reprinted as follows:
1. document. formName. item ("itemName ")
Note: in IE, you can use document. formName. item ("itemName") or document. formName. elements ["elementName"];
In Firefox, only document. formName. elements ["elementName"] can be used.
Solution: Use document. formName. elements ["elementName"].
2. Collection class Object Problems
Note: in IE, you can use () or [] to obtain collection class objects. In Firefox, you can only use [] to obtain collection class objects.
Solution: use [] to retrieve collection class objects.
3. Custom Attributes
Note: in IE, you can use the method to obtain general attributes to obtain custom attributes, or use getAttribute () to obtain Custom Attributes. In Firefox, you can only use getAttribute () obtain custom attributes.
Solution: getAttribute () is used to obtain custom attributes.
4. eval ("idName") Problems
Note: in IE, you can use eval ("idName") or getElementById ("idName") to obtain the HTML object whose id is idName. In Firefox, you can only use getElementById ("idName ") to obtain the HTML object whose id is idName.
Solution: getElementById ("idName") is used to retrieve the HTML object whose id is idName.
5. The variable name is the same as the ID of an HTML object.
Note: In IE, the ID of the HTML object can be used directly as the variable name of the subordinate object of the document; in Firefox, it cannot. in Firefox, you can use the same variable name as the HTML Object ID; in IE, you cannot.
Solution: Use document. getElementById ("idName") replaces document. idName. we recommend that you do not use variable names with the same HTML Object ID to reduce errors. When declaring variables, add var to avoid ambiguity.
6. const Problems
Note: In Firefox, you can use the const keyword or var keyword to define constants. in IE, you can only use the var keyword to define constants.
Solution: Use the var keyword to define constants.
7. input. type attribute Problems
Description: The input. type attribute in IE is read-only, but the input. type attribute in Firefox is read/write.
8. window. event Problems
Note: window. the event can only run in IE, but not in Firefox, because the Firefox event can only be used in the event. firefox must be added to the source for parameter transfer. Ie ignores this parameter and uses window. event to read this event.
Solution:
IE & Firefox:
Submitted (event) "/>...