Applies to: String Object
The indexOf method returns the character position where the first occurrence a substring occurs within a String object.
Syntax
strVariable.indexOf(substring, startindex)
"String Literal".indexOf(substring, startindex)
The indexOf method syntax has these arguments:
Part |
Description |
substring |
The substring to search for within the String object. |
startindex |
An optional integer value specifying the index to begin searching within the String object. If omitted, searching begins at the beginning of the string. |
Return value
The indexOf method returns the positon of the first occurrence of substring occurs within a given string.
Example
The indexOf method returns an integer value indicating the beginning of the substring within the String object. If the substring is not found, a -1 is returned.
If startindex is negative, startindex is treated as zero. If it is larger than the greatest character position index, it is treated as the largest possible index.
Searching is performed from left to right. Otherwise, this method is identical to lastIndexOf.
The following example illustrates the use of the indexOf method:
function firstIndex(str1,str2)
{
var s = str1.indexOf(str2);
return(s);
}
document.write(firstIndex("abcdeedd", "d"));
|
 To run the code, paste it into JavaScript Editor, and click the Execute button.
See also: lastIndexOf method, String Object methods, String Object properties |
