Heredoc (EOF) enables defining large blocks of text without escaping. The variable should be included in something like ">>>SOS ... SOS;", or ">>>EOF ... EOF;" etc. This is sometimes important in HTML context.
<?PHP $str = <<<SOS <input name="test" style="font-size:16px;width:200px;height:22px" type="text" value="test heredoc"> SOS;
The above code will show as follows in a HTML page:
In command line, the result will be showed as:
Note: The above code use "SOS" as label. You may use any label. There should be no space ahead or behind the end label. The end label should be followed by ";". The labels and content should not be in the same line.