If you see forms online which already have drop down options, the tool used for creating those is the HTML <datalist> tag. The HTML <datalist> tag is the key in providing a set of pre-determined options for a certain allocated space within a form. Users can simply choose among these options when completing the data. Once the options are reflected, the information is instantly reflected on the space.
The HTML <datalist> tag is used along with the HTML5 <input> element so the options can be placed properly within an HTML document.
The HTML <datalist> tag is similar to almost an auto-complete feature since it eliminates the need for the users to actually type in the data. It is necessary to utilize the list attribute in <input> element to be able to combine it with HTML <datalist> tag.
There is no point of comparison for <datalist> tag in HTML4.01 and HTML5. The <datalist> tag is newly introduced in HTML5. The HTML <datalist> tag is compatible with the Global Attributes in HTML5. At the same time, it also works harmoniously with the Events Attributes in HMTL5. Hence, authors of HTML documents can easily maximize the functions of the HTML5 <datalist> tag. Problem is, the HTML <datalist> tag is not recognized in all major web browsers. It is only Firefox and Opera that support this