First stage: Front-end development _ use JS to complete the registration page form Verification

2018-06-04

use JS to complete the registration page form Check

First, Step realization

　First step: Determine the event (onsubmit) and bind it to a function

Step Two: Write this function (get user input data < need to define a id> at the specified location when getting data)

Step three: Judge the data entered by the user

Fourth Step: Data legal (let form submit)

Fifth step: illegal data (give error message, do not allow form to submit)

question: How do I control form submission?

about event onsubmit: typically used for form submission, it is necessary to give a return value when defining a function. such as: onsubmit = return Checkform ()

Second, the Code implementation

JS Code:

<script>
 function checkform () {
 //alert ("AA");  /** Verify username *  ///1. Gets the data entered by the user  var uvalue = document.getElementById ("user"). Value; 　　 　 　 　 　　 
　　 //   alert (uvalue); if (uvalue== "") {//2. Error message alert ("User name cannot be empty!")  　　 );  return false/;}
 * Check password */var pValue = document.getElementById ("password"). Value;    　　
 if(pvalue== "") {　　  
alert ("Password cannot be empty!")   　　　 );    return false; } /** Verify the password */var rpvalue = document.getElementById ("Repassword"). Value;  　　 
 if(rpvalue!=pvalue) {  　　
alert ("Two times password input is inconsistent!")   　　　 );    return false; }/ * Verify mailbox */var evalue = document.getElementById ("Eamil"). Value;  　　 
 If(!/^ ([a-za-z0-9_-]) [email protected] ([a-za-z0-9_-]) + (. [ A-za-z09_-]) +/.test (Evalue)) {　　   
alert ("The mailbox format is incorrect!")    　　　　 );   return false; 
}
  }
</script>

Html section:

<action= "#"  method= "Get"  name= "RegForm"  onsubmit= "return Checkform ()">

Need to add ID at specified location

First stage: Front-end development _ use JS to complete the registration page form Verification