Trim spaces from JavaScript strings

Removing leading spaces (at the beginning) or trailing spaces (at the end) takes a single regular expression pattern and the replace() method. The "start" and "end" operators mean the beginning of a string variable or literal, or the start and end of an HTML text field's value.
To remove spaces at the beginning of a string, use this regular expression: // Declare string with spaces on both ends: var str = " I learn JavaScript "; // "g" = global: replace *all* leading spaces with empty string str = str.replace( /^\s+/g, "" ); // Surround with square brackets to clearly show spaces alert( "[" + str + "]" );
Note: we could have used a space character as pattern, but wouldn't have removed tabs, blank new lines, etc. The "\s" pattern (lowercase "s") matches *all* white space.
To remove all spaces at the end of your string, leverage this pattern instead: var str = " I learn JavaScript "; // one trailing leading space // Explicitly assign the result to modify the original string: str = str.replace( /\s+$/g, "" ); alert( "[" + str + "]" );
And now a global pattern to delete all trailing / leading whitespace: var str = " I learn JavaScript "; // Pipe character means "this pattern or that pattern" str = str.replace( /^\s+|\s+$/g, "" ); alert( "[" + str + "]" );

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