regular expression using javascript

I have a regular expression ^(?=.*?[A-Za-z])\S*$ which indicates that the input should contain alphabets and can contain special characters or digits along with the alphabets. But it is not allowing white spaces since i have used \S.

Can some one suggest me a reg exp which should contain alphabets and it can contain 开发者_C百科digits or special characters and white space but alphabets are must and the last character should not end with a white space

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Quite simply:

^(?=.*?[A-Za-z]).*$

Note that in JavaScript . doesn't match new lines, and there is no dot-all flag (/s). You can use something like [\s\S] instead if that is an issue:

^(?=[\s\S]*?[A-Za-z])[\s\S]*$

Since you only have a single lookahead, you can simplify the pattern to:

^.*[A-Za-z].*$

Or, even simpler:

[A-Za-z]

[A-Za-z] will match if it finds a letter anywhere in the string, you don't really need to search the rest from start to end.

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To also validate the last character isn't a whitespace, it is probably easiest to use the lookahead again (as it basically means AND in regular expressions:

^(?=.*?[A-Za-z]).*\S$