PGDEL/DECP03/Unit3/21
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Uttarakhand Open University
Post Graduate Diploma in e-Learning
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Unit 3.3 Web application development tools & Technologies
Functions are the JavaScript statements to perform a specific task and can return a value. JavaScript function may take zero or more parameters.
| Function |
Syntax |
Example |
| Pre-defined functions
JavaScript provides several built-in functions. e.g. functions to perform explicit type conversion like eval(). parseInt(), parseFloat() etc. |
var variable_name = function_name(parameter/s list); |
eval() function is used to evaluate a string parameter(mathematical expression) to a numeric value. val total = eval (“10+5+20”); |
| User-defined functions
User-defined functions are the JavaScript statements coded into a single unit to perform a specific task that can be used in many places whenever required. |
function function_name(parameter 1, parameter 2, . . .){ // JavaScript statements }
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<HTML> <HEAD> <TITLE> Demonstating UDF </TITLE> <SCRIPT type="text/javascript" > function udf() { alert("Hello there"); } </SCRIPT> </HEAD> <BODY onLoad="udf();"> Demonstrating User Define Function. </BODY> </HTML> |
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Work in progress, expect frequent changes. Help and feedback is welcome. See discussion page. |
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